The purpose of this study was to investigate the relationships between postformal thinking and tolerance、empathy、self-disclosure、autonomy of mature interpersonal relations. Subjects were 644, ranging from late adolescence to adulthood (range from 16 to 80 years). Questionnaire was used as the research method. Planned contrasts were used for data analysis. As postformal thinking includes relativistic thinking and dialectical thinking both, the four contrasts were relativistic thinking group and formalistic thinking group, dialectical thinking group and formalistic thinking group, dialectical thinking group and relativistic thinking group, postformal thinking group and formalistic thinking group. There are four planned contrasts on each of four dimensions of mature interpersonal relations. The results were: 1. The tolerance of the postformal thinking group was higher than the formalistic thinking group´s, the tolerance of the dialectical thinking group was higher than the relativistic thinking group´s, the tolerance of the relativistic thinking group was higher than the formalistic thinking group´s. 2. The empathy of the postformal thinking group was higher than the formalistic thinking group´s, the empathy of the dialectical thinking group was higher than the relativistic thinking group´s, the empathy of the relativistic thinking group was higher than the formalistic thinking group´s. 3. The self-disclosure of the postformal thinking group was higher than the formalistic thinking group´s, the self-disclosure of the dialectical thinking group was higher than the relativistic thinking group´s and the formalistic thinking group´s. 4. The autonomy of the postformal thinking group was higher than the formalistic thinking group´s, the autonomy of the dialectical thinking group was higher than the relativistic thinking group´s and the formalistic thinking group´s. The meanings of above findings are discussed in the paper. According to these findings, there are suggestions of future research and implications for practical applications in interpersonal relations.