【Objective】Ascertain the biological characteristics and pathogenicity differentiation of cotton Verticillium dahliae strains in the major cotton production regions in Xinjiang.【Method】Purify and cultivate the Verticillium dahliae strains to observe the biological characteristics;using identification host test to determine the pathogenicity of Verticillium dahliae.【Result】The colonial morphology of cotton Verticillium dahliae are various,most strains can bring forth microsclerotia,temperature optimum for strains growth is 25℃,some strains have endurance to high temperature Xinjiang cotton Verticillium dahliae strains can be divided into three pathotypes:strong,mild,and weak,the mild type is the majority.【Conclusion】Verticillium dahliae strains in Xinjiang have the obvious physiological differentiation phenomena,pathogenicity of VX27 strain collected in Bole region are the most strong.