Individuals with autism spectrum disorder (ASD) show an enhanced response to stressors, and gender plays an important role in stress response. Thus, autistic traits (ATs) in the general population and gender may regulate the emotion changes before and during the outbreak of COVID-19. The present study addressed this issue through a participants between quasi-experimental design, in which the epidemic status (before, during), gender (male, female), and AT groups (high ATs, low ATs) were independent variables, and positive and negative emotions were dependent variables. We used generalized linear models to estimate the effects of the independent variables and their interactions on emotions. The results showed that the COVID-19 outbreak reduced positive emotions and increased fear and anger. Furthermore, compared with before the COVID-19 outbreak, individuals with high ATs and females experienced stronger anger and fear than individuals with low ATs and males during the epidemic. The present study revealed the emotional impacts of COVID-19 and greater emotional susceptibility to COVID-19 pandemic among individuals with high ATs and females. Our findings provide prospective evidence for understanding the ASD/ATs-related enhanced response to pathogen threat-related stressors and have implications for COVID-19 crisis interventions.