Digital technologies are increasingly integrated into the daily lives of young children. However, disparities in access and use quality, known as the 'digital divide,' persist. Parents play a crucial role in narrowing this divide during early childhood, but the underlying mechanisms remain inconclusive. This study investigates how family socioeconomic status (SES) influences Chinese preschoolers' digital literacy and how parental beliefs and parental mediation mediate this relationship. A sample of 2272 parents of young children from central China completed the "Home Digital Practices Survey" (HDPS). The PROCESS results revealed the following: (1) Family SES, parental beliefs, and parental mediation significantly predicted preschoolers' digital literacy; (2) Parental beliefs and parental mediation co-mediated the impact of family SES on digital literacy; (3) Positive parental beliefs and mediation strategies were associated with better digital literacy outcomes for preschoolers. The findings have implications for parental education and highlight the importance of considering family context in promoting digital literacy among young children.