Objective To investigate the willingness of middle-aged and elderly men in rural Sichuan province to undergo human immunodeficiency virus (HIV) testing and its associated factors, providing references for promoting voluntary testing.

Methods A face-to-face questionnaire survey was conducted among 990 middle-aged and elderly men in rural Sichuan from July to August 2023. The data on demographic characteristics, HIV testing willingness, and HIV prevention protection motivation were collected. LASSO and Boruta methods were used to screen relevant variables. An XGBoost model was employed to predict HIV testing willingness, with SHapley Additive exPlanations (SHAP) for importance and interaction analyses.

Results The middle-aged and elderly men in rural Sichuan showed the HIV testing willingness rate of 53.13% and the HIV knowledge awareness rate of 35.56%. Among them, 62.02% held an attitude of relative stigma toward AIDS, and 6.36% had previously undergone HIV testing. LASSO and Boruta identified 10 key variables from 22 independent variable candidates. The XGBoost model achieved an area under the curve (AUC) value of 0.979 (95%CI: 0.963–0.995). SHAP importance analysis revealed the top five factors derived from protection motivation theory dimensions. The HIV testing willingness was positively associated with testing self-efficacy (SAV = 3.08), social support (SAV = 0.29), and awareness of HIV-related services (SAV = 0.27), and negatively associated with behavioral costs (SAV = 0.22) and external rewards (SAV = 0.20). Factors such as unmarried status, lack of HIV knowledge, and previous experience of HIV testing were primarily associated with willingness, while 45–49 years and high school/vocational school or above were mainly associated with unwillingness.

Conclusions Middle-aged and elderly men in rural Sichuan exhibit low willingness to undergo HIV testing, which is primarily associated with insufficient HIV knowledge, inadequate social support, and prevalent AIDS-related stigma. Enhancing the awareness of testing experiences may encourage testing uptake.