Objective To compare and analyze economic burden of patients with healthcare-associated infection (HAI) based on the disease diagnosis-related group (DRG), and provide support for the prevention and control of HAI. Methods Hospitalization days and medical expense of all hospitalized HAI patients were analyzed retrospectively and compared with those of patients in the same DRG in a hospital from 2018 to 2020. Results From 2018 to 2020, the number of HAI cases were 694, 1 102 and 819 respectively, and the number of cases in the same DRG were 72 707, 92 837 and 59 398 respectively; the average hospitalization days of HAI patients were higher than those of patients in the same DRG (31.07 days vs 13.05 days, 65.98 days vs 47.51 days, 35.38 days vs 13.45 days), differences were all significant (all P < 0.01). The average hospitalization expense in each year was higher than that of patients in the same DRG (122 900 Yuan vs 38 400 Yuan; 171 800 Yuan vs 41 200 Yuan; 157 500 Yuan vs 44 300 Yuan), differences were all significant (all P < 0.01). In terms of infection site, the average hospitalization expense of catheter-related bloodstream infection(CRBSI) was the highest, which was 225 700, 358 800 and 268 000 Yuan in 2018-2020. The average length of hospital stay of patients with CRBSI was 102.00 days and the hospitalization expense was 284 200 Yuan during three-year, which increased by 88.78 days and 242 700 Yuan respectively compared with those of patients in the same DRG. Conclusion HAI in hospitalized patients will significantly increase the direct economic burden of patients, controlling CRBSI is the top priority of reducing economic burden of HAI, under the DRG payment method, it is imperative to strengthen the prevention and control of HAI.