Study On Post-benefit Evaluation Of The Linked Change Of Rural-urban Construction Land

China is currently experiencing rapid urbanization, large areas of land have been occupied by expanding urban construction, especially the cultivated land, which resulted in huge pressure on cultivated land protection and food security. But against the tense situation of urban construction land, land use of rural construction is extensive, and there is very serious waste phenomenon of land resource. The policy for linked change of rural-urban construction land is an effective measure, which can promote the optimization of land use structure and layout, coordinate the development of urban-rural regions, and mitigate the conflicts between economic development and cultivated land protection. Owing to the urban and rural construction land linked in China is still at the beginning of research and experiment, and relevant theory and practice are not mature absolutely, initiating the research on the post-benefit of project should have a great significance, it can help to found the existing problems in real work and give some reasonable suggestions, and to improve related theoretical system. The main research contents of this paper are as follows:(1) Describing the current situation of land use of our country in detail, analyzing the main existing problems of land use, introducing the related research theories and results about land reclamation at home and abroad, then from the point of cultivated land protection and balancing development of urban-rural regions, the connotation of the linked change of rural-urban construction land was presented, and evaluation contents were confirmed.(2) After the comparative analysis of various post-benefit evaluation methods, firstly, the method of multi-level fuzzy comprehensive evaluation was selected in this paper, and the evaluation index comprised of economic benefits, social benefits and ecological benefit was established, including 12 evaluation indicators, the calculation method of the indexes was also determined. Secondly, weights of each index were calculated using analytic hierarchy process and expert scoring. Finally, economic benefit, social benefit, ecological benefit, and the comprehensive benefit of project were evaluated, and the score model was introduced to quantify the evaluation results.(3) Dongxiang county was selected as an example of empirical research under the guiding of above theory, after evaluation analysis, it can be found that the economic-benefit level was raised from "worse" to "good", the social one was raised from "worse" to "good", the ecological one was raised from "worse" to "excellent", and the comprehensive benefit level was raised from "worse" to "good". It is not difficult to realize that the ecological-benefit was the most obvious in project area after further analysis to the evaluation results, and achieved the integrated goal of economic, social and ecological benefit basically effectively; however, it also reflected that there are still upside potential of all kinds of these benefits, that should be pay more attention in the implementation of these projects in the future.