Objective To investigate the bacterial spectrum and drug resistance of chronic periprosthetic-joint infection (PJI) in the elderly and to provide reference for its clinical prevention and treatment. Methods A retrospective analysis was made of 76 elderly patients with PJI who underwent hip and knee arthroplasty in Guangzhou First people′s Hospital from January 2013 to October 2018. The bacterial spectrum and drug resistance were analyzed using French Automated Microbial Identification and Susceptibility Test System (VITEK2-Compact, BioMérieux, France). Results Among 76 patients, 64 were infected for the first time after the initial replacement and 12 after revision, 18 being mixed infection (with at least two bacteria) and 58 being single infection. Knee arthroplasty were performed in 51 patients, hip arthroplasty in 23, and femoral head replacement in 2. A total of 108 strains of bacteria were isolated, of which 72.22%(78/108) were gram-positive, mainly Staphylococcus aureus and Staphylococcus epidermidis, and 27.78%(30/108) gram-negative, mainly Escherichia coli and Pseudomonas aeruginosa. Bacteria varied in their resistance to antimicrobial agents. Over 60% Staphylococcus aureus and Staphylococcus epidermidis were resistant to clindamycin, erythromycin, gentamicin and penicillin, and less than 5% to vancomycin, linezolid, tigecycline, quinupeptine/dafolopin; over 70% Escherichia coli and Pseudomonas aeruginosa were resistant to cefazolin sodium, ceftazidime, compound sulfamide and ampicillin and less than 15% to piperacillin/tazobactam and imipenem. Conclusion Staphylococcus aureus and Staphylococcus epidermidis are the main pathogens of chronic PJI in the elderly, the bacterial spectrum of chronic infection different from that of acute infection, and antibiotics should be selected based on the results of drug sensitivity test.