The aim of the study was to establish a set of differential strains and to identify soybean resistant genes to Phytophthora root rot and then to apply those strains for analysis of the resistant genes Rps1a, Rps1c, and Rps1k that soybean cultivars or lines may carry. Virulence formula of 125 Phytophthora sojae isolates were determined using the hypocotyls inoculation technique, the strains, which includ 6 isolates with different virulence formulas, were applied to identify the resistance of 55 soybean cultivars or lines and resistant genes were analyzed using the gene postulating procedure. Eighteen reaction types occurred in 55 cultivars or lines and results of gene postulation indicated that 2 cultivars or lines probably carried gene Rpslc and no cultivar may carry genes Rpsla or Rpslk. A few of soybean cultivars or lines from Huanghuai Region carry Rps genes Rpsla, Rpslc and Rpslk and tend to infect by P. sojae, so resistant cultivars or lines need to be bred and popularized actively.