Objective To investigate the causes and intervention measures of healthcare-associated infection (HAI) cluster events after cataract phacoemulsification combined intraocular lens(Phaco+Iol) implantation in an eye hospital, and provide reference for the prevention and control of HAI. Methods Epidemiological investigation was carried out on 4 cases of endophthalmitis after Phaco+Iol implantation within 34 days from July 25 to August 27, 2020. Environmental hygiene monitoring on surgical environment was carried out, and comprehensive intervention measures were taken ( from October to November) to avoid the spread of HAI. Results Within 34 days, a total of 1 219 patients underwent Phaco+Iol implantation, and 4 patients developed endophthalmitis, with an infection rate of 0.32%. The 4 infected patients, with an average age of 74 years, were implanted with three different brands and models of intraocular lenses respectively. They were diagnosed with endophthalmitis at different periods from the 2nd to the 9th day after surgery, which was initially suspected to be a cluster event of HAI. A total of 13 environmental hygiene monitoring specimens from operating room were unqualified. After taking infection prevention and control measures, the qualified rate of environmental hygiene monitoring before and after intervention was compared, difference was statistically significant (P=0.006). Three different bacterial species (Staphylococcus chromogenes, Staphylococcus epidermidis, and Enterococcus faecalis) were identified from vitreous and aqueous humor specimens of 4 patients. Bacteria culture results of vitreous specimens from 1 patient was negative. After the implementation of the infection prevention and control strategy, no similar infection occurred. Conclusion Improving the awareness on HAI prevention and control, strengthening the comprehensive monitoring and management of the operating room and related departments in the hospital, as well as taking timely and targeted preventive and control measures can effectively control the occurrence of HAI cluster events.