To explore the psychological status of the Armed Police Forces recruits during the training period, and to explore its relationship with serum vitamin D level and biochemical indicators. Methods: The 198 recruits from a certain armed police department in Hubei were enrolled in this study. The mental state of the recruits were evaluated by the symptom checklist-90 (SCL-90) at the end of the 3-month training period. At the same time, venous blood samples from the recruits were collected to detect serum 25(OH)D level, liver and kidney function, and other clinical biochemical indicators. Firstly, the difference between the SCL-90 total score and item scores of the recruits and those of the national norm were analyzed. Secondly, the influence of basic demographic characteristics, lifestyle habits, and vitamin and calcium supplements on the recruits’25(OH)D level and SCL-90 scores were explored . Thirdly, the relationship between the recruits' clinical biochemical indicators and SCL-90 subscores were explored. Results: There was a significant difference in serum 25(OH)D levels between recruits with different BMI (P=0.039) and different daily milk intake (P=0.003). The SCL-90 scores of the recruits were lower than those of the Chinese norm (all P<0.01). The hostility scores of recruits of different ages were significantly different (P=0.027), and hostility scores of frequent smokers were significantly different from those of non-smokers (P=0.020). The somatization, obsessive-compulsive, and anxiety scores of recruits with drinking habits were significantly higher than those of non-drinkers (all P<0.05). Recruits with fewer than 2 hours per week of outdoor exercise showed significantly higher somatization, obsessive-compulsive, depression, anxiety, phobic anxiety, paranoid ideation, and psychoticism scores compared to those with more than 2 hours of weekly outdoor exercise (P<0.05 or P<0.01). Alanine transaminase (ALT) and aspartate transaminase (AST) displayed a linear regression relationship with somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism scores (all P<0.01). Urea and creatine kinase (CK) levels showed a linear regression relationship with phobic anxiety score (both P<0.05). Conclusion: High-intensity training has a certain effect on the mental status of armed police recruits. Smoking and drinking have an adverse effect on the mental state of recruits. Increased outdoor activity has a positive effect on adapting to training and enhancing combat effectiveness.