["Child &Family Social Work, EarlyView. ", "\nABSTRACT\nThe mental health of young children plays a crucial role in their future development. Parenting stress is a significant factor associated with young children's mental health. However, the underlying associations remain insufficiently explored. Based on the ecological system theory, emotional security theory and stress and coping theory, we investigate the indirect associations of positive parenting and parent–child relationships linking parenting stress and young children's mental health. We utilised the localised and revised Brief Child and Family Intake and Outcomes System, Parental Stress Scale, Alabama Parenting Questionnaire—Preschool Version and Child–Parent Relationship Scale to survey 1117 parents of children 3–6 years old (mean = 4.71 years, SD = 0.56 years). Results indicate a significant negative correlation between parenting stress and young children's mental health. Positive parenting and parent–child relationships (parent–child closeness/conflict) not only independently mediate between parenting stress and young children's mental health but also play a chained mediating role. This research provides further evidence of the relationship between parenting stress and young children's mental health and holds significant practical importance for the mental health development of young children in China. Parents should manage nurture stress appropriately, strengthening parent–child relationships to foster the psychological health development of young children.\n"]