This study aimed to explore the applicability of the mother-and-child drawings as a projective drawing test to distinguish the smartphone overdependence of upper-grade elementary school students, through the differences in mother-and-child drawings responses. Mother-and-child drawing and a smartphone overdependence scale were administered to 476 fifth-and sixth-grade students from three elementary schools in P and U city. Afterward, 95 smartphone overdependent students and 95 students among 336 normal group students were selected for the research. For the analysis, frequency analysis, T-test, and crossover analysis were used. The findings from the study are as follows; First, in the mother-and-child response differences, the higher the overdependence, the higher the mother-and-child overall score. In the mother-and-child grading scale, differences in size, expression, body touch, and eye contact were shown. Second, in the mother-and-child Parent-Directed Interaction response between the smartphone overdependent group and its counterpart, significant differences in mother-and-child behavior, thought, and intimacy were shown. Based on these research results, the significance and limitations of this study were discussed.