Since the outbreak of COVID-19, growing awareness of hygiene, health, and safety has led consumers to prefer safe and effective cosmetics that consider skin health. As this consumption trend continues to spread, the demand for clean beauty products has also been steadily increasing. This study applies the Health Belief Model and incorporates functional congruity to analyze the relationships between variables affecting Chinese consumers’ attitudes toward clean beauty products and their willingness to pay a premium price. Additionally, it examines the moderating effect of consumers’ prior knowledge on the relationship between attitude and willingness to pay a premium price. The main findings of the study are as follows: first, among the variables related to the Health Belief Model, perceived severity, perceived benefits had a significant positive effect on attitudes toward clean beauty products, while perceived barriers had a significant negative effect on attitudes. Second, among the variables related to the Health Belief Model, perceived susceptibility, perceived benefits, and self-efficacy had significant positive effects on willingness to pay a premium price for clean beauty products, while perceived barriers had a significant negative effect on willingness to pay a premium price for clean beauty products. Third, functional consistency had a significant positive effect on both consumers'attitudes toward clean beauty products and their willingness to pay a premium price. Fourth, consumers'attitudes toward clean beauty products were found to have a significant effect on their willingness to pay a premium price. Finally, consumers’ prior knowledge was found to have a moderating effect on the relationship between attitude and willingness to pay a premium price for clean beauty products.