A field plot culture experiment was conducted under the ecological and climatic condition of Xinjiang to study the effect of special fertilizer of drip irrigation on root growth,vigor and yield of cotton with the cultivar 293 and 710 with high yield.The results showed that compared with the control,the special fertilizer of drip irrigation had significantly increased root biomass and root activity,especially the organic-inorgaic fertilizer had significantly increased the root biomass and vigour in layer of 40～100 cm soil layer.Furthermore,it reduced the root/shoot ratio and increased the distribution percentage of photosynthetic assimilates in aerial part,especially in the reproductive organs increased that led to high yield of cotton.The differences of response to special fertilizer of drip irrigation among varieties were great,seed yield of 293 in different treatment showed the organic-inorgaic fertilizer>bio fertilizer>inorganic fertilizer>control.However,seed yield of 293 in different treatment showed the organic-inorgaic fertilizer>inorganic fertilizer>bio fertilizer>control.Therefore,it would be of great importance to institute the optimum fertilization schedule,according to the differences of response to special fertilizer of drip irrigation among varieties for abstaining high yield and high water use efficiency.