Abstract: Routine isolation way, dew chamber way, disease leaf claping with potato slices and induction with potato tuber were tested, besed on semi-composed medium of RSA plus several antibiotics. Total 186 isolates from representive areas of potato and tomato in Chongqing were obtained and purified through cutting the top of mycelium of pathogen. Bioassay of typical isolate was carried out to determine the growth and sporulation of Phytophthora infestans. The results showed that the growth rate of Phytophthora infestans on tested media is as following order: RSA>RA>RSB>SVA>RTA>LVA>VA>MA>PSA>PDA; RSB is best for sporulation, then RTA.