Objective To analyze the relation of parents' parenting efficacy with parental burnout, and to explore the moderating effect of emotional expression between the two as above. Methods A total of 951 parents of students in the middle school were enrolled as the research subjects. Parents' parental burnout, parenting efficacy, and emotional expression were evaluated by employing the parental burnout assessment scale, parents' parenting efficacy subscale, self-expressiveness within the family context, respectively. Partial correlation analysis was used to evaluate the correlation between parenting efficacy, parental burnout and emotional expression while controlling for the linear influence of other variables. The moderating effect of emotional expression between parenting efficacy and parental burnout was validated by using the PROCESS 4.1 plugin of SPSS 26.0 software. Results (1) Parents' parenting efficacy negatively correlated with negatively emotional expression and parental burnout, and positively correlated with positively emotional expression (P<0.05). Parental burnout negatively correlated with positively emotional expression, whereas positively correlated with negatively emotional expression (P<0.05). (2) After adjusting for relevant confounding factors, the interaction term between parenting efficacy and positively emotional expression, and the interaction term between parenting efficacy and negatively emotional expression exerted negative prediction effect on parental burnout (P<0.05). In conditions of low levels of positively or negatively emotional expression, parenting efficacy exhibited inapparently negative prediction effect on parental burnout, while in conditions of medium and high levels of positively or negatively emotional expression, parenting efficacy could negatively predict parental burnout prominently. Conclusion Parental emotional expression plays a moderating role between parenting efficacy and parental burnout. In conditions of medium and high levels of emotional expression (regardless of whether the type of emotional expression is positive or not), stronger parenting efficacy is associated with slighter degree of parental burnout.