Objective To investigate the late detection of HIV/AIDS cases in the elderly in Jilin Province and analyze its influencing factors， to provide theoretical basis for improving their life quality.

Methods The first CD4 values of HIV/AIDS patients aged 50 years and above living in Jilin Province were used to estimate late detection， and the influencing factors of late detection in elderly cases were analyzed.

Results The average CD4 cell count of newly reported HIV/AIDS cases aged 50 and above in Jilin Province from 1996 to 2021 was （230.55±191.97）， the low value group accounted for the largest proportion （50.8%）， and the late detection rate was 59.3% （1397/2325）. The late detection cases were mainly from sexual transmission （46.8% for same-sex and 48.2% for heterosexual contact）. From the perspective of sample sources， most of the late detection patients were diagnosed while testing for other illnesses， followed by testing and consulting. In terms of contact history， the late detection of cases of men who have sex with men was higher. The binary logistic regression analysis showed that gender， marriage， sample source and report year were the factors affecting the late detection of AIDS. The late detection rate of males was higher， and cases of married couples were more likely to be late detection. With the increase of report year， the late detection rate decreased， and testing and counseling could effectively reduce the late detection rate of AIDS.

Conclusion The CD4 cell count in the first detection of HIV/AIDS in the elderly in Jilin Province is low， and the late detection rate of male cases is high. In recent years， the expansion of voluntary counseling and testing in Jilin Province has effectively reduced the late detection rate of HIV/AIDS. At the same time， sex education should be strengthened for the elderly， healthy marital relationships should be advocated and more attention should be paid to the mental health of the elderly.