Farming - grazing transitional zone is a typical ecological fragile area. The economic growth had to rely on the combination of farming and animal husbandry due to the unique environment. Currently,low coverage grassland and grazing policies cause the shortage of fodder which affected the normal development of animal husbandry. In farming - grazing transitional zone,water resource is an important factor affecting agricultural development and determining the layout of agriculture. Therefore,it is important to explore the influencing factors affecting the distribution of yield in different regions under irrigation and analyze how to use water effectively,so as to solve the contradiction between the development and the ecological protection. The method of participatory rural appraisal was used to collect data of irrigation agriculture and the LSD,T test and regression analysis were used to analyze the data. The results showed that,firstly,the crop yield in the study area was determined by climate condition. The maize yield in each natural village fluctuated between 1200 ~ 12750(kg /hm~2). Secondly,different soil and agronomic differences led to the different yield levels. Thirdly,when the irrigation quota was 2245.5 ~ 6888(m~3 / hm~2),the water saving irrigation was effective and had very good output benefit. By evaluating the capacity of groundwater support using the water balance method,it was not suitable for large - scale development of irrigation agriculture in the study area. It concluded that the planting area should be planned reasonably based on scientific investigation,so as to ensure maximum harvest and high efficient utilization of water resources.