To explore the relationships among parenting styles, children's electronic media usage (EMU) and children's problem behaviours (CPB), 1,224 preschoolers aged 3-6 years old (52.0% boys; 30.9% aged 3 years old, 34.6% aged 4 years old, 26.1% aged 5 years old, and 8.4% aged 6 years old) and their parents were enrolled in the present study by means of a questionnaire administered as an online survey, with the primary caregivers completing the questionnaires regarding parenting styles, strengths and difficulties, and time their preschoolers spent using electronic media. The results indicated that there is a significant two-by-two correlation among the three variables. The authoritative parenting style significantly and negatively predicted recreational e-activities (REA) and CPB and significantly and positively predicted educational e-activities (EEA). The authoritarian parenting style significantly and positively predicted REA and CPB and significantly and negatively predicted EEA. A further bootstrap test indicated that children's EMU partially mediated the relationship between parenting styles and CPB.