[Objective] The slope vegetation restoration effect and dominant ecological factors in the working area of DG hydropower station in Xizang Autonomous Region were studied in order to provide a theoretical basis and technical support to increase the success rate of vegetation restoration, control soil erosion, and improve the ecological environment in the work area. [Methods] Five different types of slope (slag accumulation, soil, soil/rock mixed, rock, and concrete) were taken as the research objects, and the relative soil water content, air temperature, slope and slope aspect were selected as ecological factors. After in-situ monitoring, sampling and analyzing the entropy-weight method was used to calculate the weight scores of vegetation characteristics (species diversity, species richness, and vegetation coverage) and soil fertility (organic matter, available phosphorus, available nitrogen, and available potassium). Then the comprehensive-evaluation method was used to calculate the comprehensive score that was then combined with the range analysis to select the most dominant ecological factor. [Results] The highest comprehensive score of vegetation restoration (10.000 0) was obtained for the slag accumulation slope and the soil slope, and the effect of vegetation restoration was the best for these two slopes. The comprehensive score of vegetation restoration for the concrete slope was only 5.369 0, and the effect of vegetation restoration was poor. Different types of slope had different effects on vegetation restoration because of different ecological factors. The impact of ecological factors followed the order of relative soil water content＞slope＞air temperature＞slope aspect for the soil/rock mixed slope; relative soil water content＞air temperature＞slope＞slope aspect for the rock slope; relative soil water content＞slope aspect＞slope＞air temperature for the soil slope, concrete slope, and slag accumulation slope. Hence, relative soil water content was the most dominant ecological factor for all slopes. [Conclusion] The main ecological factor affecting slope vegetation restoration in the working area of DG hydropower station in Xizang Autonomous Region is soil relative humidity. There are great differences in the combination of optimal ecological factors for vegetation restoration in different types of slopes, among which the relative soil water content and slope of soil-rock mixed slope, rock slope, soil slope, concrete slope and residue accumulation body slope are the same, and the differences are mainly reflected in slope aspect and air temperature.