Objective: To explore the mechanism of parental psychological flexibility between home-school cooperation and parental anxiety, in order to provide a path reference for relieving parental anxiety. Methods: 1342 parents were investigated with home-school cooperation scale, parental psychological flexibility Scale and anxiety scale, and the mediation test and Bootstrap method were used to analyze the effect. Results: (1) There was a significant positive correlation between home-school cooperation and parental psychological flexibility; There was significant negative correlation between home-school cooperation and parenting flexibility and anxiety. (2) The mediating effect test showed that parental psychological flexibility played a significant mediating role between home-school cooperation and parental anxiety, and the mediating effect was -0.10. Conclusion: Home-school cooperation can affect parents’ anxiety directly or indirectly through parental psychological flexibility. Parents can reduce anxiety by promoting home-school cooperation and enhancing parental psychological flexibility.