Abstract: The low level of physical activity is a public health issue of common global concern. One of the challenges in promoting physical activity among the population is to eliminate the physical activity intention-behavior gap. By establishing a random forest model and performing feature importance analysis on the survey data from Yangpu District, Shanghai in January 2024, it is found that when an individual's perceived barriers to exercise behavior are smaller and the perceived severity of lack of physical activity is greater, the probability of an exercise intention-behavior gap is lower. It is believed that perceived barriers are the primary variables for predicting the existence or non-existence of an individual's exercise intention-behavior gap, and the perceived severity and the use of mobile media can also help eliminate the intention-behavior gap. On this basis, it is proposed to alleviate and eliminate the individual's exercise intention-behavior gap and achieve physical activity promotion through strategies such as reducing perceived barriers and enhancing perceived severity, promoting the use of mobile media, and furthering causal mechanism research, etc.