Abstract: Objective To learn the epidemic situation and tendency of HIV/AIDS in Yunnan province. Methods Adopting 4 serological and epidemiological methods such as sentinal surveillance, cross-sector survey, routine screening for high-risk people and voluntary anonymous test to collect epidemic data and reported cases data of HIV/AIDS in Yunnan province. Results Total of 105.587 high-risk people were surveyed in the whole province in 2003, of which there were 2 453 newly detected cases and 172 diagnosed AIDS patients and 81 deathe. The rate of HIV infection of venous drug addicts at surveillance sentinal was 21.2%(0.6%-63.0%),and the rate of venous drug addicts in 8 areas had reached a high level. The rate of HIV infection of male otpatients at venereal diseases clinics was 2.6%(0-10.8%),of which the rate of male out-patients at venereal diseases chinics in Menglian county of sima region was 10.8%;the IHV infection rate of pregnanat and lying-in women was 0.4(0-1.3%),of which the rate of pregnant and lying-in women in the hospitals in Longchuan county and Yingjiang county of Dehong region was 1.3% and 1.0%;the HIV infec-tion rate of unrelated people in hospitals of highly prevalent raea was 1.3%;and that of blood donors was 0.07%,the posiive rate among voluntary anonymous people was 13.1%.The infected people were mainly 20 to 30 years old male venous drug addicts of Han nationality,of which peasants and loafers took a large part,mainly distributing in Dehong, Honghe, Dali, kunming, Lincang and Baoshan of Yunnan Province. Conclusion The HIV infection of venous drug addicts prevailed with a increasing infection rate in Yunnan province,and caused HIV propagation and prevalence among sex promiscuity people.For pregnant and lying-in women,HIV infection rate had been increasing further,and the prevalence rate of unrelated people had been over 1% in the hospitals of highly prevalent areas. So the whole province was threatened by AIDS wide prevalence.