Background: Externalizing problem behaviors, such as childhood aggression, have a significant impact on adolescent delinquency and even adult delinquency and violence. Mother's attitudes and behaviors can impact the self-control and regulation of preschoolers, which in turn reflect in preschoolers' externalizing problems. Objective: This longitudinal study aimed to examine the long-term effects of maternal parenting styles on preschoolers' externalizing problem behaviors and explore the potential mechanisms. Methods: We conducted a three-wave survey among 269 preschoolers (52.8% were male) aged 3-6 years, assessing maternal parenting styles at T1, executive function and negative emotion regulation strategies at T1 and T2, and externalizing problem behaviors at T3. Results: For preschoolers, maternal authoritative parenting (T1) was significantly positively associated with executive function (T2), and negatively associated with negative emotion regulation strategies (T2) and externalizing problem behaviors (T3). Besides, maternal authoritarian parenting was significantly negatively associated with executive function (T2), and positively associated with negative emotion regulation strategies (T2) and externalizing problem behaviors (T3). Maternal parenting could not directly affect externalizing problem behaviors, but it could affect externalizing problem behaviors through the mediation of executive function and negative emotion regulation strategies. The chain mediating effects included three paths: the mediating role of executive function, the mediating role of negative emotion regulation strategies, and the chain mediating role of executive function and negative emotion regulation strategies. Conclusions: The findings underscored the importance of preschoolers' self-regulation in the cognitive and emotional domains when understanding the influence of maternal parenting styles on preschoolers' externalizing problem behaviors.