Objective To understand the job burnout and psychology defense style of Chinese soldiers during vital task, and to explore the correlation between job burnout and psychology defense style, so as to provide a theoretical basis for the intervention of job burnout in military. Methods A total of 226 soldiers were investigated by the military burnout inventory and defense style questionnaire (DSQ) when they participated in a major military training for 6 months. Results A total of 226 valid questionnaires were collected and the effective rate was 100%. The average total score of job burnout was 13.10±10.80, and the highest score (4.32±3.45) was for low self-evaluation among five factors of job burnout. The result of the Pearson correlation analysis showed that the total score of job burnout was not significantly correlated with fantasy, release or expectation, but was significantly correlated with all the other factors of defense style (all P<0.01). The result of the regression analysis found that mature defense style and immature defense style were significant factors of job burnout (both P<0.01); the higher the score of mature defense style, the lower the score of job burnout, and the higher the score of immature defense style, the higher the score of job burnout. Conclusion The job burnout of serviceman is related to their specific defense style, and the interventions can be taken accordingly.