Background <p>To understand the role mechanism of policy tools on the influence of protection behavior of middle-aged and older adults, and to provide a reference basis for the government to improve the protection policy of infectious diseases.</p> Methods <p>A questionnaire on protective behaviors was conducted in June to August 2023 using a random sampling method among 463 urban middle-aged and older adults (aged 45 and above) in 19 provinces. And the mechanism of the influence of policy tools on protective behaviors of middle-aged and older adults was analyzed through using multivariate ordered logistic regression model.</p> Results <p>The mean value of protective behavior was 3.025 among 463 middle-aged and older adults; the results of multivariate ordered logistic regression analysis showed that punitive tools, incentive tools, nudging tools, and boosting tools could directly and positively influence the protective behavior of middle-aged and older adults; self-efficacy partially mediated the influence of the four types of policy tools on protective behavior.</p> Conclusion <p>The protective behavior of middle-aged and older adults still needs to be improved, and policy tools can be utilized to intervene in their protective behaviors.</p>