Although some studies suggest that parents' and children's pro-environmental behaviors (PEBs) are associated with parent-child environmental interaction (PCI), it is unclear how PCI affects their PEBs. Specifically, how does the bidirectional parent-child dyadic effect promote the transmission of PEBs? The present study addresses this question by using the actor-partner interdependence mediation model (APIMeM). We investigate the mediation roles of family well-being (FWB) and nature connectedness (NC) in the PCI-PEBs relations based on a matched sample of parent-child dyads, including children aged 11-14 years (n = 416) and their parents (n = 416). Results showed that both parents' and children's PCI had direct actor effects on their PEBs. For both parents and children, there were indirect actor effects linking PCI to PEBs: One through FWB and NC, another through NC only. Furthermore, we found a partner effect that children's PCI predicted parents' PEBs through children's NC. These findings enrich the theoretical framework of the PCI-PEBs relations based on the actor-partner interdependence mediation model, and provide implications for improving well-being and PEBs from a family perspective.