A field experiment was conducted to study the effects of N fertilization and soil textures on cotton root characteristics and yield under conventional drop irrigation by using the method of minirhizotron technique and randomized field plots. The results showed that N fertilization and drop irrigation significantly reduced cotton length density and surface area, a significant negative correlation existed between fertigation and the two root parameters. Cotton root length densities in 0-20 cm were in an order of sand soil > clay soil > loam soil before flowering stage, but in an order of sand soil > loam soil > clay soil after flowering stage; Cotton length densities in 20-40 cm were in an order of loam soil > clay soil > sand soil, and it decreased significantly in sand soil than in other soil textures. The surface areas of coarse roots were in order of N2 (N 360 kg/hm²) > N3 (N 480 kg/hm²) > N1 (N 240 kg/hm²) > CK (no nitrogen). Correlation analyses showed that cotton root length density and surface area significantly influenced cotton yield, which indicates that decreasing cotton root length density and surface area is conducive to promoting cotton yield.