Objective  To determine the clinical epidemiological characteristics of newly reported human immunodeficiency virus/acquired immunodeficiency syndrome （HIV/AIDS）in southwestern China from 2001 to 2017.

  Methods  Clinical data of newly diagnosed HIV/AIDS from 2001 to 2017 in the West China Hospital of Sichuan University were reviewed and analyze.

  Results  A total of 1 520 228 patients were screened for HIV, including 285 983 outpatient and emergency patients and 1 234 245 inpatients. About4 037 (0.27%) patients were confirmed with HIV/AIDS. The confirmation rate increased from 2001 to 2013, followed by a slight decline from 2014 to 2017. The male to female sex ratio of confirmed HIV/AIDS was 3.49:1 from 2001 to 2017, ranging from 1.65:1 to 5.08:1. The majority of patients were identified as Han (88.23%), had low education (58.66%), and married (54.75%). Peasants/herdsman comprised 26.33% of the patients. The proportion of young (15-29 years old), and middle-aged (≥50 years old) patients and those who were unmarried and had high education (senior high school and above) increased over time. Heterosexual transmission remained stable at about 60% while homosexual transmission increased by about 15% (χ²=14.436, P＜0.005) since 2008. Transmissions through drug abuse(χ²=71.633, P＜0.005) and blood(χ²=16.672, P＜0.005) decreased. Of the 899 female newly reported HIV/ADIS patients, 77.20% were infected through heterosexual relationship. In comparison, of the 3 138 male patients, 61.41% were infected through heterosexual and 18.10% through homosexual relationships. Homosexual transmissions decreased with age, but heterosexual transmissions increased with age. Mother-to-child transmissions were concentrated in those between 0 and 15 years old (100%).

  Conclusion  Newly diagnosed HIV/AIDS cases increased over the years in the West China Hospital of Sichuan University, in particular in those of young and middle-aged, highly educated and unmarried. Heterosexual transmissions remain the main route.