Objective: To examine the application effect of body mechanics principles in the process of health workers doffing personal protective equipment (PPE). Methods: A total of 360 health workers from a Fangcang shelter hospital, also known as alternate care site, in Shanghai were involved in a centralized 1-day training concerning essential skills for taking off PPE. The training was focused on integrating body mechanics principles, including expanding the support surface, lowering the center of gravity, reducing the shift in the the center of gravity, using the principle of leverage, and creating the appropriate operating space, in the PPE doffing process. Through remote video monitoring and recording, observations were made of the physical stability, pollution risks, and operational smoothness of the health workers when they applied body mechanics principles in their actions. Results: The results of binary logistic regression showed that, compared with the actions taken without applying body mechanics principles, performing the operation of the body leaning forward and then slightly leaning backward was positively correlated with stability in the doffing process (odds ratio [O R]=3.291, 95% confidence interval [ CI]: 1.627-6.656), negatively correlated with pollution risks ( OR=0.203, 95% CI: 0.100-0.412), and positively correlated with operational smoothness ( OR=20.847, 95% CI: 8.061-53.916); performing the operation of taking off the boot sleeve in a horse-riding stance, with one foot standing ahead of the other, was positively correlated with stability ( OR=5.299, 95% CI: 1.041-26.957), negatively correlated with pollution risks ( OR=0.079, 95% CI: 0.009-0.692), and positive correlated with operational smoothness ( OR=16.729, 95% CI: 1.238-226.077); performing the operation of taking off the boot sleeve by lifting the heel and then the toes was positively correlated with stability ( OR=19.361, 95% CI: 8.391-44.671), negatively correlated with pollution risks ( OR=0.181, 95% CI: 0.084-0.393), and positively correlated with operational smoothness ( OR=10.977, 95% CI: 3.764-32.008); performing the operation of the leaning forward and keeping the face looking forward when taking off the mask was positively correlated with stability ( OR=2.935, 95% CI: 1.412-6.101), negatively correlated with pollution risks ( OR=0.123, 95% CI: 0.059-0.258), and positively correlated with operational smoothness ( OR=18.126, 95% CI: 6.665-49.297). Conclusion: In the process of medical staffs doffing PPE, correct and proper mechanical postures and actions can effectively assist medical staffs to maintain balance and stability and reduce the risks of infection, which has major significance and should be widely incorporated in personal protection skills training and applied in clinical practice.