Objective: To investigate the specific effects of early family nurturing environments on intellectual development and behavioral issues in preschool children aged 3–6 years, providing evidence-based support for early family intervention and child health care. Methods: This study investigated the early developmental processes of 300 children aged 3–6 years enrolled in the child health department of a community health service center from January 2024 to December 2025. The Family Nurturing Environment Questionnaire for Children Aged 3–6 was used to assess the family nurturing environment. The Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) Chinese Version and the Achenbach Child Behavior Checklist (CBCL) were used to assess children’s full-scale IQ (FSIQ) and behavioral development levels. Results: A total of 300 valid questionnaires were collected. Among them, 163 children scored ≥85 on the family nurturing environment scale (high-quality nurturing environment group), while 137 children scored <85 (general environment group). Children in the high-quality environment group demonstrated significantly higher FSIQ totals than those in the average environment group, with all differences statistically significant (P < 0.05). Scores in the externalizing behavior domain, internalizing behavior domain, and competence domain were higher in the high-quality environment group, while scores in the dysregulation domain were lower, all differences statistically significant (all P < 0.05). Conclusion: The family nurturing environment significantly influences children’s early intellectual development and behavioral growth. It is recommended that relevant parents continuously enrich appropriate learning stimuli in home education, utilize positive and sensitive parent-child interactions, and adopt warm and accepting parenting styles to enhance children’s cognitive abilities and promote their positive behavioral development.