Background: Parents of children with autism spectrum disorders (ASD) experience heightened levels of parenting stress and more affective symptoms. Although the relationship between parenting stress and mental health has been extensively studied, limited understanding exists regarding parenting behaviors and related factors. This study aimed to explore the role of parents' affective symptoms in the relationship between parenting stress and parenting behaviors among Chinese parents of children with ASD. Methods: A total of 185 parents participated in one online survey, reporting parenting behaviors, parenting stress, depression and anxiety symptoms. Results: (1) A higher level of parenting stress was associated with reduced positive parenting behaviors and increased negative parenting behaviors. (2) Parents' anxiety and depression symptoms mediated the relationship between parenting stress and positive parenting behaviors. Conclusion: Parenting stress has potential detrimental effects on parenting behaviors in Chinese parents of children with ASD through the mediation of parental depression and anxiety.