Objective To understand the occurrence of healthcare-associated infection (HAI) in patients with coronavirus disease 2019 (COVID-19) caused by Delta variant of SARS-CoV-2, and provide reference for the prevention and control of HAI in COVID-19 treatment hospitals. Methods Through the combination of medical record reviewing and bedside checking, HAI of all patients in a COVID-19 designated hospital on January 13, 2022 were investigated and analyzed by adoping the time point prevalence survey method. Results A total of 403 COVID-19 patients were investigated, ranging in age from 10 months to 94 years, with a median age of 36 years, the case preva-lence rate of HAI was 1.99%. There were significant differences in the prevalence rate of HAI among patients with COVID-19 at different ages, disease types as well as diagnosis and treatment location (all P < 0.05). The utilization rate of ventilator was 1.24%, 2 patients had ventilator-associated pneumonia; utilization rate of urinary catheter was 1.99%, 1 patient had catheter-associated urinary tract infection; utilization rate of central venous catheterization was 0.99%, and no patient had central venous catheter-related bloodstream infection. The main infection site was lower respiratory tract, the main pathogen was Staphylococcus aureus. Antimicrobial use rate was 1.74%, all were therapeutic and monotherapy. Conclusion With the continuous evolution and variation of SARS-CoV-2, epidemic situation in many countries and regions has rebounded, the prevalence of HAI in patients with COVID-19 caused by Delta variant is lower than that of patients with COVID-19 caused by the original strain, and there are some differences in the use of antimicrobial agents and invasive operation; the elderly, severe patients and intensive care unit patients are the groups that COVID-19 designated hospitals should focus on to prevent and control HAI.