Corona Virus Disease 2019 (COVID-19) outbreak has attracted worldwide attention. The COVID-19 outbreak is unique in its rapid transmission and results in heavy stress for the front-line health care workers (HCWs). The current study aimed to exam posttraumatic stress symptoms (PTSS) of HCWs fighting for the COVID-19 and to evaluate their sleep quality after one-month stressful suffering. 377 HCWs working in different provinces of China participated in the survey between February 1st and 5th. The demographic information was collected firstly. Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) and The Pittsburgh Sleep Quality Index (PSQI) were selected to measure PTSS and sleep quality. Results showed that one month after the outbreak, the prevalence of PTSS was 3.8% in HCWs. Female HCWs were more vulnerable to PTSS with hazard ratio of 2.136 (95% CI= 1.388-3.286). HCWs with higher exposure level also significantly rated more hyper-arousal symptoms (hazard ratio= 4.026, 95% CI= 1.233-13.140). There was a significant difference of sleep quality between participants with and without PTSS (Z value= 6.014, p<0.001) and among different groups with various contact frequency (Chi-square=7.307, p=0.026). Path analysis showed that there was a significant indirect effect from exposure level to PTSS through sleep quality (coefficient =1.750, 95% CI of Boostroop test = 0.543-2.998). In summary, targeted interventions on sleep contribute to the mental recovery during the outbreak of COVID-19. Understanding the mental health response after a public health emergency might help HCWs and communities prepare for a population's response to disaster.