The integration of rural secondary and tertiary industries (referred to as “three - industry integration”) is a key pathway to advancing agricultural and rural modernization and an important measure to achieve rural industrial prosperity under the Rural Revitalization Strategy. This study focuses on the level of three - industry integration and its influencing factors in China and its four major economic zones from 2015 to 2024. Using the random effects model and the Oaxaca - Blinder decomposition method for empirical analysis, the study finds that the level of three - industry integration has shown an overall upward trend with fluctuations and exhibits a geographical distribution pattern of “east - west - central” in descending order. From the subsystem perspective, there are significant differences in the development levels of the three - industry integration subsystems across regions, although the overall trend is upward, the development of industrial cycles is relatively slow. Human capital, urbanization, land transfer, and agricultural loans have a significant promoting effect on the integration of the three industries, but they also lead to differences in the level of integrated development across regions to some extent. Based on these findings, it is recommended to continue to focus on the development of rural industrial cycles, guide college students to return to their hometowns to start businesses, promote urbanization and land transfer, to promote high - quality development of the integration of the three rural industries.