To improve the blast resistance of C815S, a widely applicable two–line photo–thermal–sensitive male sterile in China, Gumei 4 contained rice blast risistance gene Pigm was used as gene donor to introduce Pigm into the genetic background of C815S by cross and then back cross breeding combined with molecular marker–assisted selection (MAS). Three improved sterile lines with Pigm homozygous genotype were developed through blast resistance identification and evaluation of comprehensive agronomic characters. 7CS01 showed 1st grade for blast, meant resistance; 7CS02 and 7CS03 showed 3rd grade for blast, meant middle resistance. Blast resistance comprehensive index of the improved sterile lines was raised by 58.05% and average spike number raised by 26.45%, compared to C815S.