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Background Men who have sex with men (MSM) are at high risk of HIV acquisition. Long-acting injectable-pre-exposure prophylaxis (LAI-PrEP), requiring less frequent dosing, is being studied as an alternative method to daily oral HIV PrEP. With the addition of this potential new prevention method, it expands the scope for a wider user choice and is expected to increase the acceptability and uptake of HIV prevention measures. The aim of our study was to explore the willingness to use LAI-PrEP and associated influential factors. Methods Participants were recruited from December 2020 to March 2021 through banner advertisements on web- and mobile app-based platforms on Blued, a large gay Chinese social media platform. MSM in our cross-sectional study was HIV-negative and currently lived in mainland China. Participants were asked about their willingness to use LAI-PrEP and reasons why they might be or not be willing to use LAI-PrEP. Multivariable logistic regression was used to analyze the factors associated with the willingness to use LAI-PrEP. Results In total, 969 participants met the inclusion criteria and finished the survey. Nearly twenty percent (19.5%) of participants had never tested for HIV; 66.8% of MSM had multiple male partners; and 51.6% of MSM engaged in condomless sex with their partner. About three-fifths (66.3%) of MSM were aware of PrEP, and only 3.9% of MSM had used PrEP before. The willingness to use LAI-PrEP among MSM was 74.0% (95% CI: 71.4%-76.6%). MSM with higher education levels were less likely to show a willingness to use LAI-PrEP (AOR = 0.56, 95%CI: 0.38–0.84). Participants who had a history of HIV test (AOR = 1.68, 95%CI: 1.11–2.55), were willing to use daily oral PrEP (AOR = 10.64, 95%CI:7.43–15.21), had multiple male sexual partners (AOR = 1.33, 95%CI:0.93–1.90), who used rush popper(AOR = 1.49, 95%CI:1.05–2.13), and who were aware of PEP (AOR = 1.66, 95%CI: 1.02–2.70) were more likely to show willingness to use LAI-PrEP. Conclusions In our study, MSM had quite high awareness but low uptake of PrEP. As LAI-PrEP is expected to be approved for use in China in the future, our study of MSM highlights the need for key population-focused education programs about PrEP and healthy sexual behavior. This study also provides some evidence for LAI-PrEP use among the Chinese MSM population in the future.研究背景 男男性行为者（men who have sex with men, MSM）面临极高的艾滋病病毒（HIV）感染风险。长效注射型暴露前预防用药（Long-acting injectable Pre-Exposure Prophylaxis, LAI-PrEP）因给药频率更低，正被研究作为每日口服HIV暴露前预防用药的替代方案。这一潜在新型预防手段的出现，拓宽了使用者的选择范围，有望提升艾滋病预防措施的可接受性与普及率。本研究旨在探讨男男性行为者使用LAI-PrEP的意愿及其相关影响因素。 研究方法 研究对象于2020年12月至2021年3月，通过大型华人同性社交平台Blued的网页端与移动端应用的横幅广告招募。本横断面研究纳入的男男性行为者需满足HIV检测阴性且目前居住于中国大陆。研究人员询问了受试者使用LAI-PrEP的意愿，以及愿意或不愿使用该药物的原因。采用多变量logistic回归分析与LAI-PrEP使用意愿相关的影响因素。 研究结果 最终共有969名符合纳入标准的受试者完成了调查。近两成（19.5%）的受试者从未接受过HIV检测；66.8%的男男性行为者拥有多名男性性伴侣；51.6%的受试者曾与伴侣发生无保护性行为。约五分之三（66.3%）的男男性行为者知晓暴露前预防用药（Pre-Exposure Prophylaxis, PrEP），仅3.9%的受试者曾使用过PrEP。男男性行为者对LAI-PrEP的使用意愿率为74.0%（95%置信区间：71.4%~76.6%）。受教育程度较高的男男性行为者使用LAI-PrEP的意愿更低（校正优势比（Adjusted Odds Ratio, AOR）=0.56，95%CI：0.38~0.84）。有HIV检测史的受试者（AOR=1.68，95%CI：1.11~2.55）、愿意使用每日口服PrEP的受试者（AOR=10.64，95%CI：7.43~15.21）、拥有多名男性性伴侣的受试者（AOR=1.33，95%CI：0.93~1.90）、使用过rush popper的受试者（AOR=1.49，95%CI：1.05~2.13）以及知晓暴露后预防（Post-Exposure Prophylaxis, PEP）的受试者（AOR=1.66，95%CI：1.02~2.70）使用LAI-PrEP的意愿更高。 研究结论 本研究显示，男男性行为者对PrEP的知晓率较高但实际使用率较低。鉴于LAI-PrEP未来有望在中国获批上市，本研究针对中国男男性行为人群的结果凸显了开展针对重点人群的PrEP及健康性行为健康教育项目的必要性。本研究同时为未来中国男男性行为人群使用LAI-PrEP提供了相关证据支持。