Abstract: Objective To investigate the status of social support，sense of security，sexual mental health and sexual health attitude of medical students in higher vocational colleges of Sichuan Province，analyze the mediating role of social support and sense of security in sexual mental health and sexual health attitude. Methods Using the convenience sampling method，856 medical students from three higher vocational colleges in Sichuan Province were investigated by general information questionnaire，social support scale，security scale，sexual mental health scale and sexual health attitude scale from March to May 2021. Results The scores of sexual health attitude，sexual mental health，sense of security and social support of medical students in higher vocational colleges were （45.843±9.166），（69.158±9.746），（60.490±10.627） and （52.542±8.365）points，respectively. The results of correlation analysis showed that there was a positive correlation between the sexual mental health and sexual health attitude of medical students in higher vocational colleges（r=0.287-0.571，all P<0.05），a negative correlation between sense of security and sexual health attitude（r=-0.274--0.679，all P<0.05），and a negative correlation between social support and sexual health attitude（r= -0.246--0.541，all P<0.05）. The mediating effect analysis showed that the social support of medical students in higher vocational colleges played a partial mediating role between sexual mental health and sexual health attitude，and the mediating effect was 0.097，accounting for 15.67% of the total effect. The sense of security played a partial mediating role between sexual mental health and sexual health attitude，the mediating effect was 0.169，accounting for 27.30% of the total effect. The social support and security played a chain mediating role between sexual mental health and sexual health attitude，the mediating effect was 0.036，accounting for 5.82% of the total effect. Conclusions The sexual health attitude of medical students in higher vocational colleges is at a medium level，which needs to be further improved. The nursing education should formulate targeted sexual education and training activities according to the differences of student groups，improve students' social support and sense of security，and improve their sexual psychological health status.

Key words: Medical students in higher vocational colleges, Social support, Sense of security, Sexual mental health, Sexual health attitude