To describe epidemiological trends and spatial distributions of HIV/AIDS among older adults (aged !50) in Sichuan Province, China during 2008-19, and provide scientific reference for HIV/AIDS prevention, intervention and treatment. Methods: Data on HIV/AIDS cases reported in 2008-19 was extracted from the Case Report System. The Cochran-Armitage trend test was used to determine epidemic trends. Spatial autocorrelation and spacetime analysis were conducted with ArcGIS10.6 and ArcGIS Pro2.4, respectively. Results: A total of 77 854 HIV/AIDS cases among older adults were included in the study. Newly reported cases increased from 320 in 2008 to 22 189 in 2019, and the reported incidence rate (number of new reported cases/older adult population) rose from 0.001% to 0.077%. Infections through heterosexual transmission increased from 65.3% to 98.2% of total cases in older adults in this period. Spatial analysis at the county-level showed significant clustering throughout Sichuan, with the main hot spots concentrated in the southeast. Spatiotemporal analysis indicated that most of the southeastern counties/districts were Consecutive Hot Spots. Conclusions: Older adults have become a key population in the HIV/AIDS epidemic in Sichuan; comprehensive prevention and intervention measures targeted to older adults are urgently needed to control the spread of HIV/AIDS.