Objective To investigate the influence of negative emotions on risk perception in frontline medical staff at the early stage of coronavirus disease 2019 (COVID-19) outbreak.Methods An online questionnaire survey was conducted on the dispatched medical staff of Wuhan Huoshenshan Hospital and the frontline anti-epidemic medical staff of Changhai Hospital of Naval Medical University (Second Military Medical University) from Feb. 3 to 5, 2020. The negative emotions were measured by the reduced version of negative affection scale composed of 7 negative emotions. The risk perception level was evaluated by the risk perception questionnaire of frontline anti-epidemic medical staff adapted from nursing staff risk perception questionnaire.Results A total of 220 valid questionnaires were collected, with an effective rate of 85.94%. The total score of negative emotions of frontline medical staff at the early stage of COVID-19 outbreak was 11.18±4.58, and the scores of 7 negative emotions from high to low were tension (1.92±0.90), upset (1.75±0.92), fear (1.61±0.84), impatience (1.58±0.84), sadness (1.51±0.83), trembling (1.50±00.83) and guilt (1.31±0.64). The scores of impatience, sadness, upset and guilt of non-nursing staff were significantly higher than those of nursing staff (all P < 0.05). The total score of risk perception of medical staff was 17.68±4.60, and the score of time risk dimension was the highest (3.20±1.20). The organizational risk score (3.39±1.01 vs 2.88±1.01) and time risk score (3.46±1.22 vs 3.09±1.18) of the non-nursing staff were significantly higher than those of the nursing staff (P < 0.01 or P < 0.05). There was a positive correlation between the total score of negative emotions and the total score of risk perception (r=0.499, P < 0.01). The score of each negative emotion classification had an indicating effect on different risk perception tendencies, and impatience had the most obvious indicating effect on time risk (β=0.227, P=0.033).Conclusion Medical staff with high negative emotions have high risk perception. The negative emotion management at the early stage of the epidemic can help frontline anti-epidemic medical staff to correctly understand the risk.