Abstract: In the context of implementing the national strategy of National Fitness and widely carrying out national fitness activities, busy work constrains workers' physical exercise participation, exacerbate the depletion of workers' health. Based on the data from the China Family Panel Studies, this paper empirically examines the impact of working hours on workers' physical exercise participation behaviour using the Probit and Tobit models. The research shows that an increase in working hours significantly reduces the probability of physical exercise participation and the amount of time spent in sports among workers. However, there is an "inverted U-shaped" relationship between working hours and physical exercise participation probability and time spent on sports. And, no income-promoting effect of increased working hours has not been found to affect workers' time of physical exercise participation, and the dominance of the time substitution effect results in increased working hours significantly reducing workers' participation time in sports. The heterogeneity analysis shows that there is no gender difference in the impact of increased working hours on physical exercise participation behaviour of workers, but compared with urban and engaged in agricultural workers, its inhibitory effect of urban workers and workers engaged in non-agricultural work is more obvious. Accordingly, proposals have been made as follows: to safeguard the rights and interests of overtime workers to participate in sports by means of legislation, to optimise the supply of sports services by attaching importance to the cost of workers' time, and adopt a flexible work system to reduce the workload and intensity of workers.