Objective To investigate the etiology, pathogen distribution and antimicrobial resistance of calcaneal osteomyelitis. Methods Clinical data of patients with calcaneal osteomyelitis in a hospital from January 2017 to December 2020 were analyzed retrospectively. Results There were 174 cases of calcaneal osteomyelitis, 136 of which were caused by trauma (78.2%), 32 (18.4%) were caused by diabetic foot infection. 126 strains of pathogenic bacteria were isolated, the main pathogenic bacteria were Gram-positive bacteria (70 strains, 60.3%), Staphylococcus aureus and Enterococcus accounted for 36.5% (46 strains) and 11.1% (14 strains) respectively; Pseudomonas aeruginosa (19 strains, 14.3%) was the main Gram-negative bacillus; multidrug-resistant organisms (MDROs) were isolated from 50 bone tissue specimens of calcaneal osteomyelitis, accounting for 28.7%. Univariate analysis showed that body mass index (BMI), age, cause of disease, types of pathogens and number of operations were relevant factors for MDRO infection in patients with calcaneal osteomyelitis, compared with non-MDRO infection in patients with calcaneal osteomyelitis, differences were all statistically significant (all P < 0.05); logistic regression analysis showed that age >60 years, diabetic foot combined with infection, anaerobic infection and number of operations >5 times were independent risk factors for MDRO infection in patients with calcaneal osteomyelitis. BMI 18.5-24 kg/m² was an independent protective factor for MDRO infection in patients with calcaneal osteomyelitis. Conclusion Calcaneal osteomyelitis is mainly caused by trauma and diabetic foot, the main pathogenic bacteria are Staphylococcus aureus, Enterococcus and Pseudomonas aeruginosa. MDRO infection is common, which need ratio-nal use of antimicrobial agents.