Psychiatric nurses often experience burnout and other mental health symptoms. However, few studies have examined these phenomena and gender‐specific associated factors during the COVID‐19 pandemic. We surveyed a national sample of psychiatric nurses ( N = 8971) from 41 tertiary psychiatric hospitals in China as part of a large national survey conducted during the pandemic. The Maslach Burnout Inventory‐Human Service Survey was used to assess burnout and the Depression, Anxiety, and Stress Scale‐21 was used to assess mental health symptoms. Binary logistic regression analyses were used to explore factors associated with burnout in the entire sample and separately by gender. The overall prevalence of burnout was 27.27%, with the rate in male psychiatric nurses (32.24%) being significantly higher than that in female psychiatric nurses (25.97%). Many key demographic factors (such as the male gender and marital status), work‐related variables (such as a mid‐level professional title, having an administrative position, longer working hours, more monthly night shifts, and the perceived negative impact of the COVID‐19 pandemic on medical work) were significantly associated with burnout in the whole sample. Moreover, burnout was associated with depression, anxiety, and stress symptoms in the whole sample. Gender‐specific factors associated with burnout were also identified: burnout was associated with night shifts in male psychiatric nurses, whereas it was associated with single or married marital status, a mid‐level professional title, and having an administrative position among female psychiatric nurses. The high rates of burnout and mental health symptoms in psychiatric nurses need attention from hospital administrators. While mental health symptoms, longer working hours, and the perceived impact of COVID‐19 are associated with burnout in both genders, gender‐specific factors also warrant special attention when developing gender‐specific interventions.