Objective To investigate the sleep quality, positive mental health and their relationship in naval officers and soldiers during late long-time escort. Methods A total of 154 escort officers and soldiers were selected from a naval fleet by random cluster sampling method. The Pittsburgh sleep quality index (PSQI) and mental health continuum short form (MHC-SF) for adult were used for questionnaire survey on the 180th day of the long-distance navigation. Results A total of 152 valid questionnaires were collected. On the 180th day of the long-distance navigation, the total score of PSQI (7.16±3.47) was significantly higher than the military norm (5.41±3.09, P<0.01), and 46.71% (71/152) of the officers and soldiers suffered from poor sleep quality (the total score of PSQI>7). The total score of MHC-SF was 3.57±0.99, the score of social well-being dimension was 3.59±1.07, and the score of psychological well-being dimension was 3.71±1.06, which were all significantly higher than the national norm (3.24±1.00, 3.14±1.20, 3.44±1.10, all P<0.01). The total score of PSQI of escort officers and soldiers was negatively correlated with the total score of MHC-SF and the scores of emotional well-being, social well-being and psychological well-being dimensions of MHC-SF (r=-0.34, -0.40, -0.32, -0.28, all P<0.01). Conclusion During the late long-time escort, nearly half of the escort officers and soldiers have sleep problems, while the overall positive mental health is well and the sense of well-being is high. Sleep problems adversely affect the positive mental health of officers and soldiers.