The impact of digital technology on the younger generation is profound and far-reaching. In a digital home environment, parental mediation of children's access to the Internet, digital devices, and their device use will either directly or indirectly affect children's digital attitudes and behaviors. Based on the ecological techno-microsystem theory, this study aims to examine the influence of parental mediation of Internet use and smartphone interference on children's Internet literacy and problematic smartphone use. A cross-sectional study was conducted in China and the data of 2465 elementary school students (mean age = 10.43 years, SD = 0.99, 47% girls) and their parents were collected through online and offline surveys. Structural equation model analysis indicated that parental mediation of Internet use reported by children was positively associated with children's Internet literacy (both self-regulation and reflection and critical analysis) while negatively associated with problematic smartphone use. Besides, parental smartphone interference reported by children was positively related to their reflection and critical analysis and problematic smartphone use. We also observed that children's self-regulation negatively predicted their problematic smartphone use. Further analysis showed notable discrepancies between "what parents report" and "what children perceive". Additionally, the consistency between how parents mediate children's Internet use and how parents manage their smartphone usage has a complex influence on children's digital attitudes and behaviors. Current findings contribute to expanding our understanding of the important role of parents in a digital home and could further provide some practical guidance for parents to manage their children's digital use.