In order to clarify inheritance mechanism of fertility restoration for cytoplasmic male sterility (CMS) in a new Gossypium barbadense restorer line Hai R which was found in the fertility test crossing of G. hirsutum CMS lines with G. barbadense germplasms. 23 fertility segregation populations of F2 and backcross were used to analyze the inheritance of fertility restoring gene(s) of Hai R. The result showed that Hai R had one major dominant gene (RfB) to control the CMS fertility restoration and this fertility restoration gene functioned at the sporophytic level. The sterile cytoplasm background might not only influence the transmission rate of male gamete but also that of female gamete when the restorer gene was recessive. It could be deduced that this fertility restoration gene might come from G. harknessii cotton, Hai R is of value in the application of cotton interspecific hybrid breeding. In order to clarify inheritance mechanism of fertility restoration for cytoplasmic male sterility (CMS) in a new Gossypium barbadense restorer line Hai R which was found in the fertility test crossing of G. hirsutum CMS lines with G. barbadense germplasms. 23 fertility segregation populations of F2 and backcross were used to analyze the inheritance of fertility restoring gene (s) of Hai R. The result showed that Hai R had one major dominant gene (RfB) to control the CMS fertility restoration and this fertility restoration gene functioned at the sporophytic level The sterile cytoplasm background might not only influence the transmission rate of male gamete but also that of female gamete when the restorer gene was recessive. It could be deduced that this fertility restoration gene might come from G. harknessii cotton, Hai R is of value in the application of cotton interspecific hybrid breeding.