Abstract: Objective To estimate the size of high-risk population for HIV infection and the number of people living with HIV/AIDS in Guilin and provide evidence for AIDS prevention and control. Methods The estimation was based on the related data from sentinel surveillance, case report, specific survey and other sources with workbook method. Results It was estimated that there were 4 398 people living with HIV/AIDS (aged 15-49 years) in Guilin at the end of 2011. The HIV infection rate in people aged 15-49 years was 0.157%. Among the HIV infected people, 2649(60.23%) were infected through heterosexual contact, 979(22.26%) were through injecting drug use, and 770(17.51%) were through homosexual contact. Conclusion The AIDS epidemic level remained to be low in Guilin in 2011 and sexual contact was the major transmission route.