PurposeEnvironmental and health concerns are considered the most significant motivations for organic food purchasing behaviour (OFP). This study focuses on the roles of health and environmental concerns in OFP in China, aiming to explore whether there are differences in the effects and mechanisms of these two concerns.Design/methodology/approachWe use the PLS-SEM to conduct empirical tests, drawing from survey data collected from 628 Chinese consumers.FindingsThe results showed that the OFP was influenced differently by health and environmental concerns. Specifically, the total effect of environmental concern on OFP outweighs that of health concern, whereas the opposite is true for direct impacts. Additionally, environmental and health concerns can influence OFP through attitude and subjective norms, although the specific mechanisms vary. Environmental concern affects OFP more through subjective norms, whereas health concern affects OFP mainly through attitude. Meanwhile, functional value quality was a significant moderator that enhanced the indirect effect of motivation on OFP.Originality/valueA theoretical framework is constructed to explore the role of two types of motivations in OFP within emerging economies like China, revealing their mechanism and interaction effect with functional values.