[Objective] The objective of the study is to analyze the impact of different cropping systems on crop yield, soil bulk density and soil water content in Lanzhou City and to find the optimum cropping system in this area.[Methods] The potato(P), maize(M) and faba bean(B) was selected as test crops under 9 annual rotation patterns (P-P-P, M-M-M, B-B-B, P-B-P, M-P-M, M-B-P, B-B-P, M-M-B). The soil bulk density, soil moisture, crop yield and economic benefits under different rotation patterns were analyzed.[Results] P-M-P, P-B-P, M-P-M, M-B-P and B-B-P could significantly reduce soil bulk density in 0-40 cm soil layers, but had no significant effect on soil bulk density of 40-60 cm soil layers. The influence of rotation systems on soil water content was similar to that of water consumption, the order of the effects of crop types on soil water content, water consumption were maize > potato > faba bean, and WUE were potato > maize > faba bean, respectively. Under M-M-M treatment, the soil water content was the lowest, and water consumption was the highest, WUE of B-B-P treatment was the highest. The yield of rotation cropping was higher than that of continuous cropping. In 2016, compared with continuous cropping P-P-P treatment, the crop yield under P-M-P, P-B-P, M-B-P and B-B-P treatments increased by 40.37%~79.28%. Compared with continuous cropping B-B-B treatment, the crop yield under M-M-B treatment increased by 23.56%; Compared with continuous cropping M-M-M treatment, M-P-M treatment increased by 10.51%. Compared with continuous cropping, rotation cropping would more increase in crop yield and economic benefits.[Conclusion] With respect to soil bulk density, WUE, crop yield and economic benefits, P-B-P and P-M-P were superior to the other seven rotation patterns, which could improve soil environment, and increase yield and economic benefits, and should be encouraged in Lanzhou City. The economic benefits under M-B-P was lower than P-B-P and P-M-P treatment, M-B-P had higher WUE, which could improve WUE.