This study examined whether the perceptions of the theory of planned behavior (TPB) and individual and environmental factors related to healthy eating changed after the COVID-19 pandemic among adults living in Daqing, China. Data were collected through two rounds of online surveys conducted from April to May 2021 and from March to April 2023, using a questionnaire previously validated for use in Daqing. Using the snowball sampling method, 571 adult participants were recruited, most of whom were Daqing oilfield workers or members of their families. Multiple linear regression analyses were used to determine if the differences in the perceptions of the TPB and dietary environments exist during and after the pandemic after controlling for potential confounders. Scores of several subcomponents of TPB and mean scores of longterm intentions increased but scores of subcomponents and overall mean of motivation decreased after the outbreak. Multiple linear regression showed that only motivation for healthy eating decreased after the pandemic. Influenced by the pandemic, people increased their healthy eating behaviors. Nevertheless, as the pandemic subsided and the pace of life accelerated, people tended to choose convenient foods over healthy options. Consequently, the motivation for healthy eating has declined post-pandemic compared to during the pandemic.