| Climate data was collected five stations in the west of Jilin province, the five stations include Baicheng,Tongyu,Qianguo,Qian'an and Changling. Daily soil temperature,precipitation and wind speed data are used from 1951 to 2003. The statistics theory of SPSS,EXCEL and wavelets function of MATLAB6.5 are used to analysis the change trend of average precipitation,temperature and wind speed for 50-year and change of primary weather factors are analysised the interannual and interdecadal variations,growing season and some important growing period of corn. Then on the basis of change of primary weather factor, theoretical support is provided for sustainable development of agriculture in the west of Jilin province.This study area is located at semiarid region which is an eco-frailty area. The climate type is temperate semi-aridity.Heatresources are adequate.Precipitation is inadequate,temporal and spatial distribution of precipitation is unbalanced, Evaporation is excessive, Especially in spring precipitation is low, erratic, and often happens with gale.Agricultural production is restricted by the disadvantage weather factor. There are many studies on the issue of drought, usually they pay attentions to annual change of precipitation, but a few study on months,dekad and pentad in the growing season of corn.. In this paper the change of precipitation in sowing date,spike formation stage,filling stage was studied. Also the change of≥10℃accumulated temperature,the length of growing season,soil temperature at various depths were studied, especially the study on change of wind speed by wavelets function of MATLAB is a creative attempt. The aim of this paper is to opens out the climate change in the west of Jilin province from every aspect and search the best combination between corn growth and climate resource, so a better corn cultivation can be find to adapt climate change in the future.Results show: the first day on which Tmean constantly equal or exceeds≥10℃is more and more advance, and the last day on which Tmean constantly equal or exceeds≥10℃is more and more later, Lengthening of growing season ensure sowing earlier or later; the accumulated temperature≥0oC is increasing at a rate of 88.6℃/10a; The soil temperature is increasing at different rate, soil temperature of the depths of 5cm is approaching to the line of 9℃in the second dekad of April, which is defined as the germinative temperature in this paper, some years, the temperature exceeded 9℃at the end of 1990s, the trend of temperature will exceed this line in recent years; Soil temperature of the depths of 5cm in the first dekad of May had exceeded 9℃line at the prophase of 1960s; Soil temperature of the depths of 5cm in the first dekad of May exceeded 9℃line since 1951. Soil temperature of the depths of 10cm is approaching to the line, and it has exceeded the line in the third dekad of April at he prophase of 1980s, Soil temperature of the depths of 10cm in the first dekad of May exceeded 9℃line since 1951.The average precipitation is 408.57mm during the growing season, the precipitation is increasing from the first dekan of April to the third dekan of July, then it is decreasing to the end of growing season, the third dekad of July has the most precipitation is 52mm. The precipitation is decreasing with a rate of 12.3mm/10a, and it has obvious 10a rainy—rainless long cycle surge and 1—2a less longer cycle surge. A dry—wet cycle is 16a, and it will be in the wet cycle until 2018, so we should get ready to fight drought in the coming 10—year.The precipitation in corn sowing time (the third dekad of April,the first dekad of May)is 8.24mm,11.1mm. The precipitation in the third dekad of April is decreasing witha rateof 0.8mm/10a, but precipitation in the first dekad of May is increasing with a rate of 1.22mm/10a. Before the sowing date (the second dekad of April) and after the sowing date (the second dekad of May), the precipitation are decreasing with a rateof 0.8mm/10a,0.1 mm/10a. The precipitation of the second dekad of April has 5—10a rainy-rainless cycle surge, it will be in the wet cycle until 2011. The precipitation of the third dekad of April has 6—7a rainy-rainless cycle surge, it will be in the dry cycle until 2011. The precipitation of the first dekad of May has 15a rainy-rainless cycle surge, it will be in the dry cycle until 2015.The precipitation in spike formation stage (the third dekad of July,the first dekad of Aug),filling(the first dekad of Sep,the second dekad of Sep,the third dekad of Sep)are decreasing with the different rate and has rainy-rainless cycle surge respectively. The research shows the precipitation in spike formation stage,filling trends to be dry, so we should do something for fighting drought.The average wind speed is 3.59m/s,and change trend of wind speed is decreasing since 1951; The wind speed value is increasing from 1950s to 1960s, then is decreasing after 1960s, it shows that the jump point of change is 1987 from strong to weak, and it is significant increase trend from 1990. The average wind speed has 15a strong-weak cycle surge, it will be in the weak cycle until 2015. During one year, wind speed is the strongest in April (4.78m/s),and is the weakest in August(2.61m/s). Wind speed in Spring is the strongest (4.44m/s), then Autumn(3.38 m/s),Winter(3.12 m/s),Summer(3.00 m/s).The wind speed of four seasons in a year are all decreasing, but has different trend in different decades. The decreasing trend of Spring in 1990s is significant, it has the largest contribution to the decreasing trend of 50a; The decreasing trend of Summer and Autumn in 1980s is most evident, has the largest contribution to the decreasing trend of 50a;The decreasing trend of Winter in 1960s is most evident, has the largest contribution to the decreasing trend of 50a.To the change of four Seasons, decreasing trend of Winter is most evident, then Spring,Autumn,Summer. So decreasing trend of Winter is the the main reason of the decreasing trend of 50a. On the basis of the change of primary weather factor, a appropriate adjustive measure is found to develop the agriculture in the west of Jilin province: The sowing date is advanced, then in order to search the best combination between corn growth and climate resource, cultivation is changed and seed is treated before sowing. The increasing length of growing season ensure sowing later is possible too, then the corn can be prevented from strong wind in seeding stage.
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