Abstract: In this study, the grey correlation analysis was used to analyze the factors affecting runoff formation and sediment yield in 14 runoff plots with different standing forest conditions in the central Tianshan Mountains.The research results revealed that there were the differences of the factors affecting runoff formation and sediment yield in these plots.The factors affecting sediment yield were in an order of precipitation>standing forest density>canopy live branch height>thickness of litters>canopy density>slope; the factors affecting runoff formation were in an order of precipitation>thickness of litters>canopy density>standing forest density>canopy live branch height>slope.The standing forest conditions affecting runoff formation and sediment yield were as follows: the natural forests were in an order of immature forest 3>nearmature forest>immature forest 4>mature forest>young growth>immature forest 2>immature forest 1; the plantations were in an order of mingled forest>tending forest pervious to light>pruning tending forest>forest without tending; and the shrubberies were in an order of the shrubberies with 0.6 coverage>the shrubberies with 0.8 coverage.