In order to explore the relationship between college students' understanding of social support, loneliness and mobile phone dependence, 316 college students were surveyed by understanding social Support Scale (PSSS), mobile phone addiction Index scale (MPAI) and loneliness scale (UCLA). The results showed that loneliness had a complete mediating role between friend support and inefficiency, and that individual friend support had a positive impact on the inefficiency of mobile phone dependence through loneliness. Suggestions on the parent‐child relationship and children's mental health.