This study investigated the effects of Sandplay therapy on smartphone overdependence, impulsiveness, and interpersonal problems in college students. A survey was conducted on 359 four-year college students, and 10 smartphone overdependent students were selected for both the experimental and control groups. The experimental group received 10 sessions of Sandplay therapy. Results showed that Sandplay therapy reduced the degree of overdependence, impulsiveness, and interpersonal problems in smartphone overdependent college students. Qualitative analysis identified common themes such as “being left alone,” “a side of myself I want to hide,” and “struggling to escape.” This study highlights the potential of Sandplay therapy as a treatment program for smartphone overdependence in college students. Limitations and future research directions are discussed.