China has implemented natural forest resource protection projects and ecological construction projects such as returning farmland to forests, which have made outstanding contributions to building an ecological barrier in the upper reaches of the Yangtze River and to promoting sustainable economic development in the Yangtze River Basin. When evaluating the effectiveness and impacts of vegetation restoration after the implementation of ecological projects such as returning farmland to forests, assessments of the effects of various factors are key steps to promote optimization of regional vegetation restoration and improvement of the ecological environment. Based on MODIS MOD13Q1 data, this study used the Theil Sen slope and the Mann-Kendall trend test, the baseline evaluation method, and the spatiotemporal geographic weighted regression model to quantify the spatiotemporal changes, restoration effects, and restoration mechanisms of vegetation at different time scales. The results show that:(1) the vegetation coverage is in good condition. By the end of 2019, 91% of the regional vegetation in Sichuan Province had improved, and the vegetation coverage in the northeastern Sichuan Basin, southern Sichuan Province, southeastern Wumeng Mountains, and northwestern Sichuan Plateau was relatively high. However, the vegetation coverage in and around Chengdu was low. (2) The temporal and spatial differences in the effectiveness of vegetation restoration are significant. The vegetation restoration in regions accounting for 98.68% of the province's area produced obvious results. High-value areas, which were concentrated in most areas of Sichuan Province, except for the Chengdu Plain, accounted for 71.47% of the area. (3) The influence of climate change on vegetation change is mainly insignificant. Temperature and precipitation have weak influence on vegetation restoration in Sichuan Province. Geographical environmental factors such as altitude and >35° slope area ratio are mainly weak inhibition. (4) Under the relatively stable climate background, the socioeconomic factors represented by per capita fiscal expenditure, cultivated land area and per capita GDP are important influencing factors for improvement of vegetation restoration. The vegetation restoration effect and key climate, geographical environment and socio-economic factors revealed by the study can provide certain theoretical support for the optimization of vegetation restoration policies.