Promoting the integration and development of rural industries is the objective requirement to realize the rural revitalization. Division of labor is the premise and foundation of industrial integration and development. The emergence of industrial integration and development will inevitably lead to a new form of labor division. There is mutual penetration between division of labor and industrial integration and development. We studied transaction activities in search of answers for labor division problems. Under the premise of revealing the internal mechanism of the effects of labor division and transaction efficiency on the integration and development of rural industries, we constructed an evaluation system based on labor division theories, which is used to measure and analyze the level of integration and development of rural industries in 31 provinces and cities (excluding Hong Kong, Macao and Taiwan) from 2006 to 2018. The results suggest that China's integration and development of rural industries is moving from a low-level starting stage to an accelerated development stage. We measured China's rural transaction efficiency during 2006 to 2018. The results show that the overall development level of transaction efficiency in China's rural areas has improved, but there is a lot of room for improvement. On the basis of measuring the level of integration and development of rural industries and rural transaction efficiency, we empirically tested the impact of transaction efficiency on the level of the integration and development of rural industries using Hansen threshold regression model. The results suggest that rural transaction efficiency significantly improves the level of the integration and development of rural industries, and a unit increase in rural transaction efficiency leads to a 0.1419 unit increase of the level of the integration and development of rural industries. The threshold effect results show that when the rural transaction efficiency is low (i.e., less than or equal to 0.5379), the improvement of rural transaction efficiency has an inhibitory effect on the level of the integration and development of rural industries, and when rural transaction efficiency reaches a higher level (i.e., above 0.5379), the improvement of rural transaction efficiency has a significant positive effect on the level of the integration and development of rural industries. In general, rural transaction efficiency has a "U" shape effect on the level of the integration and development of rural industries. However, China's rural transaction efficiency has not yet crossed the "U" threshold. In the short term, the increase of rural transaction efficiency may restrict the integration and development of rural industries, but in the long run, improving the efficiency of rural transactions and increasing the central government's financial support to local governments are still the key measures to promote the integration and development of rural industries in the future. According to the conclusion of the study, the following policy suggestions are put forward:continuously improving the efficiency of rural transactions, increasing the intensity of fiscal and taxation support to farmers, and promoting the integrated construction of the market system in an orderly manner. This study can be used for reference on how to improve the efficiency of rural transactions, and promote the integration and development of rural industries, which is of great significance for promoting rural revitalization.