This research examines the effect of interpersonal problem influenced by self-differentiation and aim on verifying mediating effect of basic psychological needs between them. For this research, the total of 327 data was collected by conducting on/off-line survey to 4-year-course university students on both genders, and the data was analyzed by SPSS 21.0 and Amos 18.0. Also, bootstrapping examination technique was conducted to verify the significance evaluation of mediating effect based on verified research model. Summarizing the research result, Firstly, self-differentiation and interpersonal problem showed negative corelation as the interpersonal problem reduce as self-differentiation level is high. Secondly, self-differentiation and basic psychological needs showed static corelation as the basic psychological needs are fulfilled as the self-differentiation level is high. Thirdly, the research showed the basic psychological needs between self-differentiation and interpersonal problem are partially mediated. Therefore, the research can be interpreted as the basic psychological needs are satisfied when the self-differentiation level is high, leading to reduce interpersonal problem, accordingly.