To investigate the associations between subjective perception of impacts and willingness to change dietary habits in China after experiencing the outbreak of the 2019 novel coronavirus disease (COVID-19), an online questionnaire survey was carried out and 22,459 respondents in mainland China participated in the study, with an average age of 27.9±7.8 years old. Of them, 84.5% self-reported epidemic concern (middle or above), and 60.2%, 66.3% and 66.8% self-reported impact (middle or above) on psychology, life, work respectively. 31.9%, 46.0% and 41.0% of respondents reported their willingness to reduce their dietary intakes of salt, fried foods, and sugary foods, respectively. The stratified analysis of multinomial logistic regression models showed that, respondents with higher psychological impact were more likely to increase their dietary intake of salt, fried foods, sugary foods. Except as aforesaid, most respondents with higher epidemic concerns and higher impacts on psychology, life, work were more likely to reduce eating salt, fried foods, sugary foods. After the epidemic, early stage of positive improvement to a proper diet was observed, whereas the opposite tendency was also found in some respondents with higher impact on psychology. Thus, there is an urgent need for health care and lifestyle intervention policies for different subgroups.