Abstract: Phytophthora root rot, incited by Phytophthora sojae, is an important disease of soybean. Growing resistance cultivars has been the most effective way to control the disease. The objective of this study was to identify Phytophthora resistance genes in the modern soybean cultivars or lines by application of the gene-for-gene hypothesis, and screen effective resistance cultivars or lines to P. sojae for disease control. One hundred and twenty-four soybean cultivars or lines were identified for their responses to 12 strains of P. sojae using the hypocotyls inoculation technique, 51 reaction types occurred, 98 cultivars or lines were resistant to 1 to 12 strains, respectively, while 26 cultivars or lines were susceptible to all 12 strains. By comparisons of the reaction types of differential soybean cultivars or lines, reaction types of 13 cultivars of lines were consistent with the reaction patterns of a single gene， reaction types of 33 cultivars or lines were consistent with two-gene combinations, these cultivars or line were deduced that carry single known genes or two-gene combinations, respectively. There were 37 reaction types elicited by 52 cultivars or lines are novel reaction types。Most of identified cultivars or lines were resistant, but great difference existed in number and resistance level of resistant cultivars or lines among soybean production regions. There was similar genetic background and resistance level among most of resistant cultivars or lines growing in the same soybean production region.