Abstract: Objective To explore the relationship between calcaneus bone density and stress fracture,and provide evidence for the prevention of stress fracture. Methods Twenty-three male recruits who suffered from stress fracture during the training in December 2017 were selected as the observation group,and another 19 healthy recruits with age and sex matched who had participated in the same training were selected as the control group.Their calcaneus bone density was measured by the same technician using ultrasonic bone densitometer. Results There was no significant difference in age,height and weight between the two groups.The Z score of calcaneus bone density in the observation group was （-0.383±0.903） g/cm²,and it was （0.247±0.897） g/cm² in the control group,the difference was significant （P=0.030）. Conclusion We suggest that calcaneus bone density of military cadets and athletes should be examined,so as to achieve early screening,diagnosis and treatment,and to provide health guidance for the high-risk population.