Objective To explore the mediating effect of death avoidance on the relationship between knowledge of thanatology and self-exploratory behaviors in death education among medical undergraduates. Methods A questionnaire survey was conducted among undergraduates from a university of Chinese medicine using the Chinese version of the Death Attitude Profile Scale (including dimensions: fear of death, death avoidance, natural acceptance, escape acceptance, and approach acceptance), the Thanatology Knowledge Questionnaire, and the Death Education Self-Exploratory Behavior Questionnaire. Results Death avoidance was negatively correlated with both knowledge of thanatology (r=-0.204, P<0.01) and self-exploratory behaviors in death education (r=-0.147, P<0.01), while knowledge of thanatology was positively correlated with self-exploratory behaviors in death education (r=0.172, P<0.01). Knowledge of thanatology had a significant direct effect on self-exploratory behaviors in death education, and also an indirect effect through the mediation of death avoidance (indirect effect value = 0.009), with the mediating effect accounting for 14.24% of the total effect. Conclusion The score of knowledge of thanatology among medical undergraduates can directly affect their self-exploratory behaviors in death education, and can also indirectly influence such behaviors through death avoidance. Based on this, universities need to construct a multi-dimensional intervention system: on the one hand, improve students' knowledge reserve by optimizing the design of thanatology courses and strengthening practice in clinical death scenarios; on the other hand, carry out targeted death exposure interventions (such as hospice care practice and death experience activities) to alleviate medical students' death avoidance tendency. This will help break the vicious cycle of ‘knowledge deficiency - death avoidance - inhibition of exploratory behaviors’ and ultimately achieve a substantial improvement in self-exploratory behaviors in death education.