Objective: To explore Hawthorne effect on the hand hygiene compliance of health care workers (HCWs) in intensive care unit, and to provide reference for the rational use of Hawthorne effect to strengthen the hand hygiene management in medical institutions in the future. Methods: The difference of compliance between direct observation method and concealed observation method was compared. The data were imported and exported using application program of sensor-controlled workplace. SPSS 26.0 was used for statistical analysis of the hand hygiene implementation rate of HCWs in the past one years. Results: The hand implementation rate in the concealed observation group was 81.8% from July 2020 to December 2020, and that of the direct observation group was 88.0% from January 2021 to June 2021, with statistical significance (P＜0.05). In the concealed observation group, the highest rate of hand hygiene was 90.3% for nurses, 74.3% for medical staff, 50.2% for medical technic staff, and 60.5% for other workers. In the direct observation group, the rate of hand hygiene rose to 93.6% for nurses and 84.0% for medical staff. The hand hygiene implementation rate of medical technic staff increased to 80.0%, and that of other staff increased to 87.0%, with statistical significance between the two groups (P＜0.05). The hand hygiene implementation rate of the direct observation group before contacting with patients, before aseptic operation and after contacting with surrounding objects was higher than that of the concealed observation group, and the difference was statistically significant (P＜0.05). Conclusion: The hand hygiene implementation rate of medical staff affected by Hawthorne effect under direct observation has been improved, but it is still necessary to further strengthen the hand hygiene management of medical staff, especially the personalized management of staff on different positions.