Objective To analyze the clinical data of monkeypox (mpox) cases in Chengdu, to investigate the clinical characteristics of patients with mpox complicated with human immunodeficiency virus (HIV) / acquired immunodeficiency syndrome (AIDS), and provide reference for clinical diagnosis and treatment. Methods Mpox patients admitted to Public Health Clinical Center of Chengdu between June 29 and August 8, 2023 were continuously included. Patients were divided into an observation group and a control group based on whether they were complicated with HIV/AIDS. The clinical characteristics of two groups of patients were observed and compared. Results A total of 56 patients were included, all of whom were male; Age range from 19 to 51 years old, with an average of (31.6±5.9) years old; There were 23 cases in the observation group and 33 cases in the control group. Except for age, perianal lesions with infection, number of rashes, diarrhea, CD4+ lymphocyte count, CD4/CD8 ratio, syphilis, chest CT abnormalities, rash duration, and length of hospital stay (P<0.05), there was no statistically significant difference in epidemiological data, clinical features, auxiliary examinations, treatment, and intensive care unit admission between the two groups of patients (P>0.05). There was a statistically significant difference between the Ct values of throat swab nucleic acid and blister fluid nucleic acid in the total population [(30.1±4.4) vs. (23.4±3.8); t=5.462, P<0.001]. Conclusions Mpox patients complicated with HIV/AIDS are prone to persistent, diverse, and severe lesions due to relatively lower CD4+ lymphocyte counts. Therefore, it is necessary to actively provide symptomatic treatment and prevent complications for patients.