COVID-19, a public health emergency of international concern as declared by WHO, is rapidly sweeping the world. Emerging evidence on risk perception and public responses during the pandemic (e.g. SARS, H1N1) implied that risk perception could be highly related to emotion or even mental health (Qian, et.al, 2003; Raude & Setbon, 2009; Bults, et.al, 2011). This study was based on the PsyCorona Survey, an international project on COVID-19 covering over 56,000 participants from 96 countries. Specification curve analysis (SCA) was used to examine the relationship of risk perception of COVID-19 with emotion and self-rated mental health, which considers all reasonable model settings to avoid subjective bias on modelling choices. Firstly, 162 multilevel linear regression models were established for risk perception and emotion, all of which indicated that high risk perception of COVID-19 significantly increases the level of negative emotions (median β=0.24, P<0.001) and reduces the level of positive emotions (median β=-0.18, P<0.001). Moreover, higher risk perception was also associated with worse mental health (β=-0.19, P<0.001). We further used SCA to explore whether the relationship between risk perception and mental health is mediated by emotion. Among the 54 regressions of mental health on risk perception and emotion, 36 models showed a strong mediation effect, with no significant direct effect of risk perception on mental health after controlling for emotion. We concluded that the risk perception of COVID-19 could influence emotion and ultimately have impact on mental health.