An empirical analysis based on China's 2021 Land Economic Survey data, examining the impact of internet use on planting structure adjustments, revealed the following: First, internet use can significantly reduce the proportion of grain cultivation by farmers, leading to a “de-grainization” of the planting structure. This conclusion remained valid after addressing endogeneity issues using instrumental variables in a two-stage least squares estimation. The results remained robust after conducting sensitivity tests using alternative independent variables. Second, heterogeneity analysis by grouping household heads by gender showed that the impact of internet use on planting structure varied under different household head gender conditions. Third, internet use can reduce the proportion of grain cultivation and cause a “de-grainization” adjustment in the planting structure by improving farmers’ access to financial credit availability and reducing the costs of economic crops. According to the research results, it is necessary to firmly hold the bottom line of ensuring food security, pay attention to agricultural production activities of different types of households, and establish multiple paths to promote the “grain-oriented” planting structure.