Objective To study the compliance and correctness of hand hygiene(HH) of staff in intensive care units (ICUs) of a tertiary first-class hospital, and provide theoretical basis for HH intervention. Methods In April 2023, staff in 17 ICUs of this hospital were performed on-site survey by infection control staff, and monitoring forms about HH compliance and correctness were filled out. Results A total of 874 HH opportunities were observed with the concealed observation method, 501 HH opportunities were implemented, the compliance rate was 57.32%, 273 HH opportunities were correctly implemented, with an correct rate of 54.49%. The compliance and correct rate of HH among staff in different ICUs varied significantly. Compliance and correct rates of HH among staff with different jobs were statistically different: HH compliance rate of cleaners (31. 97%) was lower than that of nurses (63. 83%), doctors (58.77%) and other personnel (58.14%); HH correct rate of cleaners (30.77%) was lower than that of nurses (58.17%). The causes for not implementing HH among staff with different jobs and at different HH opportunities were statistically different: the rate of not implementing any HH measures after contact with patients (84.75%) was higher than before contact with patients (41.27%), before clean and sterile manipulation (30.00%), as well as after contact with blood and body fluid (45.45%). The rate of not implementing any HH measures after contact with the patient's surrounding environment (66.67%) was higher than before contact with patient as well as before clean and sterile manipulation. The rates of incomplete HH steps and insufficient HH time among staff with different jobs were statistically different: The rates of incomplete HH steps of other personnel (82.35%) was higher than that of doctors (52.63%). The rates of insufficient HH time of doctors (82.46%) and nurses (78.18%) were higher than that of cleaners (51.85%). Conclusion The implementation of HH among different occupational groups and at different HH implementation opportunities in ICU is significantly different, which should be intervened based on their characteristics.