The invention discloses a gossypium barbadense chromosome segment capable of remarkably improving verticillium wilt resistance of gossypium hirsutum and molecular markers of the gossypium barbadense chromosome segment. The gossypium barbadense chromosome segment D4-1 is derived from gossypium barbadense H7124, is located in NO. D4 chromosome of cotton chromosome sets, and is identified through 11 pairs of SSR (simple sequence repeat) markers (including NAU3392, NAU6992, NAU6993, NAU3791, cgr6409, JESPR220, NAU5294, NAU7290, ZHX1, ZHX6 and ZHX29). DNA of the gossypium barbadense H7124 is taken as a template, the 11 pairs of SSR markers are adopted for amplification simultaneously, and a chromosome segment capable of simultaneously containing 11 SSR marker specific bands is the chromosome segment D4-1 of the gossypium barbadense H7124. A disease index of a gossypium hirsutum introgression line containing the chromosome segment is obviously lower than that of a gossypium hirsutum receptor control variety Sumian 8. The gossypium barbadense chromosome segment and the molecular markers thereof are applied to the verticillium wilt resistant molecular breeding of cotton, the verticillium wilt resistance of the cotton can be greatly improved, and the breeding efficiency of the cotton is improved.