Abstract: As the support of modern agricultural science and technology, agricultural machinery service can effectively improve the agricultural total factor productivity, ensure the national food security, ensure the continuous increase of farmers’ income and achieve the sustainable agricultural development. The article uses data envelope analysis and Tobit regression analysis, based on the production and operation status of 612 rice family farms in the Yangtze River basin, studies the impact of agricultural machinery service on the total factor productivity of rice family farms and the heterogeneity of the impact of “agricultural machinery service subject” and “agricultural machinery service machine type”, and further explores the mechanism of agricultural machinery service affecting total factor productivity of rice family farm by means of intermediary model. The results show that agricultural machinery service can positively affect the total factor productivity of rice family farm; the influence of different agricultural machinery service subjects on the total factor productivity of rice family farm is as follows: local cooperatives or companies＞nonlocal companies＞other farmers＞self-service, and large and medium-sized agricultural machinery is more conducive to improving the total factor productivity of rice family farm than small agricultural machinery; agricultural machinery service has an impact on the total factor productivity of rice family farm through “labor substitution” and “scale change”. All regions in the Yangtze River Basin should actively cultivate localized and comprehensive agricultural machinery service organizations, encourage and support the upgrading and application of large-scale and intelligent agricultural machinery and equipment, vigorously improve the application rate of agricultural machinery service in agricultural production links of rice family farms, and then reduce labor input, promote the large-scale management of land, and optimize the allocation of agricultural production factors, so as to improve the total factor productivity.