目的  参考社会认知理论，研究上海市外来未婚女工在性行为中安全套使用情况及其影响因素。方法  采用整群抽样的方法，在上海市3个区随机抽取了3家工厂，对1 154名外来未婚女工进行问卷调查。在校正了人口学信息后用Logistic回归分析社会认知因素，包括艾滋病（AIDS）预防认知、自我效能、技巧策略、社会心理问题与安全套使用的关联。结果  在完成调查的1 154名外来未婚女工中，有482人（41.8%）在最近6个月中发生过性行为，其中61人在每次性行为都能坚持使用安全套，仅占12.7%。校正了人口学信息后，单因素Logistic回归显示：安全套使用的相关因素包括安全套使用的自我效能(AOR=1.86; 95%CI=1.15~3.01)、使用安全套的技巧和策略(AOR=10.86; 95%CI=6.21~19.00)以及自尊(AOR=2.11; 95%CI=1.34~3.31)。多元Logistic逐步回归分析显示：筛选出自尊（ORm=1.96, 95%CI=1.18~3.24）和安全套使用技巧与策略(ORm=10.16, 95%CI=5.78~17.87)决定了安全套使用。结论  上海外来未婚女工在性行为中安全套使用率低，应通过加强该人群自尊、提升安全套使用的技巧和策略来倡导安全性行为，降低AIDS等生殖健康风险。

Objective  To investigate the condom usage of unmarried female migrant workers in Shanghai during sexual intercourse and relevant influencing factors according to social cognition theory. Methods  A total of 1 154 unmarried female migrant workers from 3 factories in 3 districts of Shanghai were selected and the questionnaire survey was conduct by using the cluster sampling method. After demographic information was corrected, social cognition factors was analyze by Logistic regression, including correlations between condom usage and prevention knowledge of HIV/AIDS, self-efficacy and skill and strategy of condom usage, and psychosocial problems. Results  Among 1 154 unmarried female migrant workers who completed questionnaires, 482 (41.8%) of them  had sexual intercourses during past 6 months. Only 61 (12.7%) of them used condom consistently. After demographic information was corrected, univariate Logistic regression analysis showed that factors relevant to condom usage were self-efficacy of condom usage (AOR=1.86; 95%CI=1.15-3.01), skill and strategy of condom usage (AOR=10.86; 95%CI=6.21-19.00), and self-esteem (AOR=2.11; 95%CI=1.34-3.31) Multivariate stepwise Logistic regression analysis showed that self-esteem (ORm=1.96, 95%CI=1.18-3.24) and skill and strategy of condom usage (ORm=10.16, 95%CI=5.78-17.87) determined the condom usage. Conclusion  The rate of condom usage of unmarried female migrant workers in Shanghai is low. Self-esteem and skill and strategy of condom usage should be improved to promote safe sexual intercourse and decrease reproductive and health risks such as AIDS.