Based on the results of reservoirs compensative regulation in main stream of the Yellow River, combined qualitative with quantitative analysis, active and negative functions to environment on mid-downstream of the Yellow River were impersonality discussed by Longyangxia and Liujiaxia reservoirs regulation. Active functions included increasing water supply, increasing ice prevention guarantee rate and decreasing water interception at Lijin profile; negative included increasing river channel sedimentation and affecting capacity of the river to carry larger volumes of water. The results indicated that ice prevention guarantee rates of Lanzhou and Huayuankou profiles were increased so as to reduce ice flood occurring probability, and water interception rate at Lijin profile was reduced 26%. Through analyzing on environment compensation effect of the Yellow River, notice should be focused on environment compensation.