Academic procrastination of graduate students is a common phenomenon, and the mentoringrelationship is a very important teacher-student relationship for graduate students. However, themechanism by which the mentoring relationship affects academic procrastination of graduate studentsis still unclear. To explore the relationship between graduate student mentoring interactions, mentors’negative evaluations, positive psychological capital and academic procrastination. A survey of 337graduate students was conducted using the Teacher-Student Interaction Questionnaire, GraduateAcademic Procrastination Scale, Brief Fear of Negative Evaluation Scale and Individual PositivePsychological Capital Scale. Results show that: (1) Tutoring relationship is negatively correlated withpostgraduate academic procrastination. (2) The fear of tutor’s negative evaluation plays a mediated rolein the negative prediction of academic procrastination of graduate students. When the teacher-studentguidance relationship is poor, the graduate students are more likely to show the fear of tutor’s negativeevaluation, and this phenomenon will further lead to high academic procrastination. (3) The mediatedeffect of fear of tutor’s negative evaluation on mentoring relationship and academic procrastination ismoderated by positive psychological capital. The results of this study provide evidence for reducingacademic procrastination in graduate school.