English as a foreign language education is a top national priority in China, and improving learners' English language proficiency is a concern. However, most research focuses on how to enhance English proficiency in the educational environment. Investigations of the impacts of family environment on English language development are limited. This study explored the relationship between family environment and English language proficiency among 975 first-year Chinese undergraduate students. One-way ANOVA, regression analysis, and mediation analysis were performed to determine the variations in English proficiency among Chinese university students based on their family socioeconomic status and parenting styles, how well these predicted Chinese university students' English achievement, and whether parenting styles mediated the link between family socioeconomic status and English proficiency. The results indicated that although the effect of family socioeconomic status on English proficiency appeared minimal, neglectful parenting, rather than authoritative parenting, had a significantly positive influence on English proficiency. This study also provided evidence of the mediating role of parenting styles between family socioeconomic status and English outcomes.