BackgroundAlthough maternal childhood maltreatment has been associated with offspring externalizing symptoms, little is known about the potential mechanisms that contribute to breaking the intergenerational effect of maternal childhood maltreatment. ObjectiveThe current study aimed to (a) investigate the intergenerational effect between maternal childhood maltreatment and offspring externalizing symptoms in the Chinese family; (b) examine maternal supportive and harsh parenting as potential mediators of this intergenerational effect; and (c) explore the moderating roles of paternal support parenting, as well as paternal harsh parenting, in this mediation process of maternal supportive and harsh parenting. Participants and settingThe sample consisted of 1111 mother-father-child triads from Beijing, recruited when the children were one and three years old. MethodsMothers completed the Childhood Trauma Questionnaire, and both parents completed the Infant-Toddler Social and Emotional Assessment and Comprehensive Early Childhood Parenting Scale. ResultsOur results showed that maternal childhood maltreatment was a risk factor for offspring externalizing symptoms at T2 (β = 0.24, t = 6.51, p < .001), and this effect was mediated by maternal supportive (indirect effect = 0.03, 95%CI = [0.02, 0.05]) and harsh parenting (indirect effect = 0.03, 95%CI = [0.02, 0.07]) at T1. Furthermore, paternal harsh parenting moderated the indirect effect of maternal childhood maltreatment on child externalizing symptoms through maternal supportive parenting. ConclusionsThese findings contribute to our understanding and provide valuable information for disrupting the intergenerational effect of maternal childhood maltreatment.