Shiyang River Basin is located in the east of Hexi Corridor in the Gansu Province. It is one of the most serious water shortage and ecological vulnerable regions. Finding out the relationship between groundwater and natural conditions and human activities has important practical significance to research and solve the water resource utilization and ecological problems. Regression analysis method was used to study the influence of the basin climate change and agricultural production and development to the groundwater level in Shiyang River Basin. The results indicate that rainfall and evaporation have a small impact on groundwater in the long run. The influence coefficient of rainfall and evaporation on the groundwater level in Wuwei region was below 0.004, meanwhile the influence coefficient was below 0.001 in Minqin region. However，runoff and change of grain yield are the primary causes of decline in groundwater level. The coefficients of runoff impact on the groundwater level in Wuwei and Minqi region were 1.381 and 6.008. At last, through the least squares regression model, an equation was determined, which describes the relationship between groundwater level and runoff, total output. The model has higher simulation accuracy after verification. Wuwei average groundwater level forecast to fall 0.945m per year, while 0.919m per year in Minqin in the future.