Based on the rainfall data and hydrological data from May to September in the east part of the north slope of the Qilian Mountains, we analyze the effect of artificial rain enhancement from 2010 to 2020 by using four mathematical statistical test methods, including non-randomized experiments, using sequence, regional comparison, regional double ratio and regional regression. The results show that artificial rain enhancement tests in the east part of the north slope of the Qilian Mountains are positive effects, proved by the four methods of effect evaluation. The effectiveness tests of region contrast, region double ratio and region regression pass the test of significance level α≤0.10. Through the analysis of the four evaluation test methods, the regional historical regression test method uses a large sample size, avoiding the artificial selection of historically similar weather is prone to introduce numerous subjective biases and controversial operating procedures, resulting in the smallest false effect and the highest efficacy compared with other tests, which can be used as the final evaluation result. The average relative cloud-seeding effectiveness in the eastern northern slope of the Qilian Mountains from 2010 to 2020 is 26%. The impact of large-scale artificial rainfall on the ecological environment improvement of the Shiyang River basin in the eastern northern slope of the Qilian Mountains from 2010 to 2020 is further evaluated. The analysis finds that the annual average runoff of the Shiyang River increases by 124.6%, and the annual average discharge of the Caiqi section in Minqin increases by 124.3%. The groundwater level in Minqin Basin rises by 2.46 m, and the water area of Qingtuhu Lake, which has been dry for nearly half a century, continues to increase.