Abstract: The mechanism and contribution of interface layers including forest canopy layer，forest litter layer，and forest soil layer to water transfer of forest vegetation in Qilian Mountains have been analyzed in this paper．The results indicate that in the water transfer process，the water quantity and energy have been converted and changed by interface layers with all ways．As the results，the ineffective wastage of water decreases and the water energy condition tends to stabilization．The mixed stands have more capability of water transfer with compound layers and different ages’structure．The water capabilities of soil and runoff are good indexes in weighing the water transfer capability of forest ecology．The tend of runoff from small to big of the main forest vegetation in Qilian Mountains is alp shrubs，Picea crassifolia stands mixed with shrubs，Picea crassifolia and moss stands，middle and low mountain shrubs．