Taking the northwest region of China as a case, this study developed separation and quantitative evaluation method to explore ecological restoration benefits from the artificial precipitation projects during 2018-2022. The methodology was conducted by comparing the linear trend rate difference of vegetation indicators (vegetation coverage, net primary productivity NPP, ecological quality index) between baseline climate condition (climate change combined with artificial precipitation) and climate change condition. Results showed that: (1) Compared with those in 2013-2017, the regional average vegetation coverage, NPP, and ecological quality index from April to September during the period of project implementation (2018-2022) increased by 1.7%, 40.9 gC/m², and 2.9, respectively. (2) The project implementation enhanced vegetation coverage by 49.2%, NPP by 35.9%, and ecological quality index by 43.4% of the land area in the study area. For example, the vegetation coverage with annual average increment in (0,0.1\]%/a was expanded by 30.4%, which was 10.4% for the ranges of (0.1, 0.2\]%/a and 4.6% for the ranges of (0.2, 0.3\]%/a, the areas of annual average increment higher than 0.3%/a were accounted for 3.8%. (3) The ground validation results of the Qilian Mountain artificial rainfall enhancement experiment showed that, the extents of vegetation coverage, NPP, and ecological quality index in the operation areas showed 13.6%, 47.0%, and 35.8% higher than that in the control area, respectively. This method could provide technical support for the fine evaluation of ecological benefits from artificial precipitation projects.