目的: 探索中国成都男男同性性行为人群(简称“男同”)人类免疫缺陷病毒(human immunodeficiency virus，HIV)暴露前预防用药(pre-exposure prophylaxis，PrEP)行为-认知偏差的现状和影响因素，以明确PrEP干预的重点人群并设计实施有针对性的干预来缩小这个偏差。方法: 在2021年11—12月期间开展了一项面向HIV阴性男同的横断面调查，由中国成都本地男同社区组织招募和筛选研究对象。收集研究对象的社会人口学特征、PrEP认知和PrEP适用性评价指标等信息。遵循《中国HIV暴露前预防用药专家共识》，本研究中PrEP适用的高危行为学指标包括(在过去6个月有以下行为之一)：没有一直使用安全套、有HIV阳性性伴、确诊性传播疾病、药物滥用和使用过暴露后预防用药(post-exposure prophylaxis，PEP)。采用Logistic回归模型进行单因素和多变量分析。结果: 在纳入的622名研究对象中，52.6%(327/622)客观符合PrEP的高危行为学指标，但只有37.9%(124/327)认为自己是PrEP的适用对象，余下的62.1%(203/327)存在行为-认知偏差；85.9%(281/327)听说过PrEP，其中14.2%(40/281)以医务人员作为PrEP信息获取渠道。在327名行为导向PrEP使用适宜对象中，47.1%知晓如何获取PrEP药物，33.0%有过正规PrEP咨询经历，93.3%周围没有或少有使用PrEP的朋友，54.1%PrEP知识得分在8分及以上，66.7%报告过去6个月有2位及以上同性性伴。在控制年龄、研究对象招募来源等背景变量后，能够正确判断自身为PrEP使用对象(即不存在PrEP行为-认知偏差)的6个促进因素包括：PEP使用史[调整后的优势比(adjusted odds ratio，OR_A)=2.20，95%置信区间(confidence interval，CI)：1.33~3.63]、PrEP可及性(OR_A=1.69，95%CI：1.06~2.68)、认识更多正在使用PrEP的朋友(OR_A=4.92，95%CI：1.77~13.65)、PrEP知识(OR_A=2.21，95%CI：1.38~3.56)、多性伴关系(OR_A=1.77，95%CI：1.07~2.94)以及自评高HIV感染风险(OR_A=4.02，95%CI：1.73~9.32)。药物滥用和PrEP信息获取渠道等与PrEP行为-认知偏差无统计学关联。结论: 中国成都男同人群PrEP行为-认知偏差高。PrEP行为干预与促进项目应重点考虑辅助男同正确评估自身HIV感染风险，提升PrEP知识，提供规范PrEP咨询和培育男同社群同伴支持环境等。

Objective: To explore the discrepancy between behavioral-indicated candidacy and perceived candidacy (behavioral-perceived gap) and its associated factors of human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM), so as to identify the focus population of PrEP interventions and to design and implement targeted interventions. Methods: We recruited a sample of 622 HIV-negative MSM who were regular clients of a community-based organization located in Chengdu, China, from November to December 2021. A cross-sectional questionnaire was used to collect the participants' information on social demographics, PrEP-related knowledge and cognitions, and risk behaviors. In this study, behaviorally eligible for PrEP was defined as performing at least one type of high-risk behavior in the past six months, including inconsistent condom use, sex with an HIV-positive partner, confirmed sexual transmitted infections (STI) diagnosis, substance use, and post-exposure prophylaxis (PEP) experience. Logistic regression models were fitted, and multivariate analyses were adjusted for social demographics. Results: Among the 622 eligible participants, 52.6% (327/622) were classified as behaviorally eligible for PrEP. Only 37.9% (124/327) of the participants perceived themselves as appropriate candidates for PrEP and 62.1% (203/207) had discrepancy between behavioral-indicated and perceived candidacy. 85.9% (281/327) had heard of PrEP, and 14.2% (40/281) accessed PrEP information through health care providers. Of the 327 participants eligible for behavior-indicated PrEP use, about half (47.1%) knew how to obtain PrEP medication and 33.0% had a professional PrEP counseling experience. The majority (93.3%) had no or few friends using PrEP. 54.1% scored eight or above in PrEP knowledge level. 66.7% reported having two or more sexual partners in the past six months. After adjusting for age and recruitment channel, we found six factors that were associated with perceived candidacy for PrEP, including PEP use [adjusted odds ratio (OR_A)=2.20; 95% confidence interval (CI): 1.33-3.63], PrEP availability (OR_A=1.69; 95%CI: 1.06-2.68), a greater number of PrEP-using friends (OR_A=4.92; 95%CI: 1.77-13.65), PrEP know-ledge (OR_A=2.21; 95%CI: 1.38-3.56), multiple sexual partnership (OR_A=1.77; 95%CI: 1.07-2.94), and perceiving a higher risk of HIV infection (OR_A=4.02; 95%CI: 1.73-9.32). Substance use during sex and PrEP information channel were not statistically associated with this beha-vioral-perceived gap. Conclusion: We observed a high discrepancy between behavioral-indicated and perceived candidacy for PrEP among Chengdu MSM in China. Future PrEP implementation efforts should be made in skills training in assessing HIV infection risk, increasing PrEP knowledge, providing professional PrEP counselling, and fostering PrEP support environment.