| The 21st century's national strategy of water resources and its related scientific issues has become an important issue concerned by global people. Climate change is one of the major global environmental problems and its influences to hydrology and water resources are one of the frontier research problems of hydrological science in 21st century. Atmospheric circulation variation and the evaporation of water etc. change the circulation and cause to space-time distribution of water. However, human activities also are the important factor caused problems of water resources. In all, under the influences of global change and human activities, the contradiction between supply and demand of water will be increasingly prominent, water environment will be worsening, and water resources available for human will further decrease. So it is necessary to make further research on water resources.Fenhe River is the second branch of Yellow River, and its runoff and sediment is one of the important sources of the Lower Yellow River. Now the Fenhe River is facing with many problems such as the shortage of water resources, the discontinuous flow, the drops of underground water level and the water pollution and so on. The main influencing factors causing runoff and sediment changes of Fenhe River include climate change and human activities. So it contains important significance in researching the influences of climate factors and human activities on runoff and sediment of Fenhe river watershed. The paper mainly takes some research as follows:First, we analyzed the annual and inter-annual variation of runoff and sediment, and the results show that there is obvious downward trend and wave character of runoff and sediment. But the downward trend of runoff is more remarkably than sediment and the former inter-annual variation is more prominent than the latter. The changes of them stay mainly from June to September of years. Before the 20th Century, the most years of Fenhe river valley is high flow period and after that is low water period. We carry out an analysis of mutation detection and period by using M-K and Wavelet Analysis. As it turned out, the time of abrupt changes of runoff and sediment is 1979 and 1982 and their periods are all about 14 to 18 years.Second, on the basis of analysis of rainfall and temperature, we find that the trend of rainfall dropped as a whole in the past years and the decrement is -17.34mm/10a. The rainfall in the 1960s and 1970s is more than long-time average annual value; the rainfall was decreasing since 1980s; in the seasonal change of rainfall, the biggest influence to the annual variation of rainfall is the summer. The temperature was increasing from 1959 to 2005 and the climatic tendency rate is 0.273℃; the temperature in spring and winter was ascending more than other seasons. The time of abrupt changes of rainfall is 1984 and 1993, and its period is 14 to18 years; the time of abrupt changes of air temperature is 1992 and its period is mainly 14 to 17 years.Finally, on the basis of correlation analysis between air temperature, rainfall and runoff and sediment, the results show that the rainfall and runoff and sediment have significant correlation, and related coefficient is 0.66 and 0.55; and the runoff of this valley increased with increasing of rainfall and decreasing of air temperature. Through the wavelet analysis, we find the seasonal change of runoff and rainfall is consistent with its annual variation and there is the most obvious change in the summer. At the same time, we analyzed the influence of climate and human activates on runoff by using quantitative method and the results show that the main reason caused runoff decreased is human activates which influence quantity is 76.99%.Based on the above discussions and according to the qualitative analyses, we believe that the main anthropogenic reasons that caused runoff decreased include many such as coal exploiting, water-and-soil conservation measures, land utilization, over development of groundwater and so on.
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