Winter wheat -summer maize rotation system is the most common rotation planting system in Guanzhong Region of Shaanxi Province. In this study, the environmental impacts(including energy consumption, land utilization, water utilization, global warming, acidification,eutrophication, water toxicity, soil toxicity, and human toxicity)of this system were evaluated by using life cycle assessment(LCA),on the basis of 1 ton of grain production. The primary data were collected from Fuping County and Yangling District of Guanzhong Region with different tillage practices. Results indicated that the ecological-environmental impact index was 0.166 9 and 0.378 8 for Fuping and Yangling, respectively. The dominating potential impact factors on the environment in two locations were different. In Fuping, eutrophication was the primary factor, whereas water toxicity was the main potential factor in Yangling. In the winter wheat-summer maize rotation system,eutrophication, water toxicity and acidification were the major risks to the ecological environment, and their impact indexes were respectively 0.078 3, 0.020 2 and 0.016 4 in Fuping, and 0.110 5, 0.214 1 and 0.023 2 in Yangling. Irrational fertilization and excessive insecticide spray led to the environmental loads in the winter wheat-summer maize rotation system in the Guanzhong Region.