Exploring the impacts of farmers’ Internet use on the level of deepening agricultural labor division is of great significance for promoting the integration of small farms into the modern agricultural economic system and promoting the modernization of agriculture and rural areas. Based on the micro-farmer data of the CFPS in 2018, this research analyzed the impacts of farmers’ Internet use on the deepening labor division of agricultural production and explored the influencing mechanism and the heterogeneity of region, age, and Internet access by the OLS model, the endogenous switching regression model, and the moderating effect model. Results show that the proportion of farmers using Internet in the whole sample is relatively low, only 36.03%. The average level of the division of agricultural production of farmers using Internet is 0.584, which is higher than that of farmers without Internet use, indicating that Internet use significantly promotes the deepening labor division in agricultural production. From the perspective of the moderating effect mechanism, the high cost of searching information and reducing contract cost can make Internet use promote the deepening labor division of agricultural production more significantly. The influence of Internet use on the level of division of agricultural production is heterogeneous: for farmers who use computers to access Internet, the old generation and in the eastern region has a more obvious promoting effect on the deepening division of agricultural production. Based on the above results, this paper provides the following policy suggestions: strengthening the construction of information infrastructure in rural areas, improving the Internet application ability of rural residents, standardizing the agricultural division of labor market system and optimizing the agricultural and rural trading market environment.