Abstract: We combined the single spore isolation technology and Williams identification method to isolate single spores of Plasmodiophora brassicae from nine major Chinese cabbage producing areas in China and identify their physiological races，to obtain more types of single-spore physiological races. A total of 281 single-spore stains were obtained and identified by Williams identification，these single spores belong to 15 types of physiological races other than No. 5 physiological race in the system. Among them，191 single-spores were of the No. 4 physiological race accounting for 67.97%. The dominant physiological race in the 9 regions was No. 4.

Key words: Cruciferae vegetable crop, Plasmodiophora brassicae, single spore isolation technology, identification of physiological races