Using 50 SSR makers to analysis genetic diversity among Phytophthora resistant soybean cultivars(lines),265 allelic variants were detected among the cultivars(lines) with average 5.3 alleles per SSR locus.The average genetic similarity coefficient 0.3124,indicating that significant genetic difference existed among the cultivars(lines).Clustering analysis showed when the similarity coefficient was 0.33 the cultivars(lines) were divided into six groups,and the cultivars or lines with the same geographical origin were clustered together.Those cultivars or lines with the same or similar resistance type to Phytophthora sojae were clustered into the same group,it indicated that they should have closer genetic relationship,and should be selectively used.Near-isogenic lines of cultivars Williams and Clark with single Rps gene were different from Chinese Phytophthora resistant soybean cultivars or lines, and could be used to widen the genetic background of Chinese soybean cultivars.