Abstract: In order to learn the status of HIV/AIDS epidemic in Yunnan province, the HIV prevalence and AIDS case data have been collected by using 4 sero - surveillance methods which include sentinel surveillance, cross - sector survey, HIV routine screening for high risk groups and voluntary anonymous HIV testing. Total 95 755 samples of high risk groups and defined sub - population groups have been tested, and 1 503 HIV positive people have been found. 151 AIDS cases had been diagnosed and 91 of them were dead. According to the injecting drug users in Simao and Zhaotong, 7 prefecture are classified as high level epidemic region;The HIV prevalence in male STD pa-tients is 2.7%(0-13.4%),especially in which from Ruili county of Dehong prefecture is 13.4%; the HIV preva-lence in female STD patients is 2.3(0-7.4%);The HIV prevalence in pregnant women is 0.2(0-2.2%); espe-cially in which from Longchuang county of Dehong prefecture is 2.2% and its great increase has been found in Long-chuang,Chuxiong and Lijiang; the HIV prevalence in underground prostitutes and clients in 2.0% and 1.8%,re-spectively; The HIV prevalence in unlinked sample of high level epidemic region,blood donors and voluntary anony-mous tests are 1.6%,0.02%,and 8.0%,respectively.Majority of the positive persons is 20-30 year old male who are injecting drug users,Han nationality,unemployed and peasants.Most of them distribute in Dehong,Honghe,Da-li,Kunming and Lincang. The HIV epidemic has spread to the whole province through injecting drug users and the HIV rate is increasing rapidly in some.areas. HIV transmission and epidemic have also been detected in sexually active groups. The prevalence in unlinked sample of high level epidemic region is over 1% and this indicates a rapid increase of AIDS cases in the future. HIV epidemic in Yunnan is very serious.Education and intervention activities in high risk groups are urgently needed.