Background: The main objectives of this study were as follows: (1) evaluate the prevalence of burnout syndrome among doctors, (2) establish associations with demographic factors in China, and (3) examine the mediating role of psychological attachment in the relationship between job burnout and career calling. Methods: This cross-sectional survey was conducted by administering an online questionnaire in May 2016. The survey was performed across Thirty provinces. In total, A total of 3016 Chinese doctors were selected as participants, of which 2617 completed valid questionnaires (effective response rate: 86.77%). Results: The overall prevalence of burnout symptoms among Chinese doctors was 85.79%. Little variance was reported for burnout symptoms according to age (Waldχ 2 = 6.843, P < 0.05, OR < 1), professional title (Waldχ 2 = 13.110, P < 0.05, OR > 1), and daily working hours (Waldχ 2 = 7.226, P < 0.05, OR > 1). However, the burnout of Chinese doctors was found to be associated with psychological attachment (B = − 0.6433, P < 0.0001) and career calling (B = 0.3653, P < 0.0001); furthermore, psychological attachment (B = 0.2350, P < 0.001) mediated the relationship between job burnout and career calling. Conclusion: Burnout symptoms among Chinese doctors were prevalent and associated with age, professional title, and long working hours. Chinese doctors aged 20-30 experienced a much higher level of burnout symptoms. The longer hours doctors worked, the more likely they were at risk of burnout symptoms, especially among attending physicians. Doctors who endured high-level burnout tended to exhibit decreasing psychological attachment, which threatened their sense of career calling. Finally, this paper proposed related explanations for the function mechanisms based on both theoretical and practical perspectives.