As the future direction of modern agriculture, agricultural informatization (AI) and its economic effects are worth exploring because they can well promote digital agriculture. Based on the existing research results, we propose six hypotheses around the economic benefits of AI and construct the geographically and temporally weighted regression (GTWR) model with a sample of 30 Chinese provinces over the period 2001–2020 for validation. Specifically, starting from farmers’ income and regional economic growth, the entropy value method is used to construct the AI indicators, and the GTWR model is constructed to analyze the effect of AI. Furthermore, the transmission mechanism of AI was explored from the perspective of agricultural industry structure upgrading. The following conclusions were drawn. First, the level of AI in China has increased significantly, and meanwhile its spatial correlation has also strengthened year by year. Second, AI demonstrates a positive correlation with farmers’ income growth and regional economic development, which means that it has become an important contributing factor of rural economic output. Third, agricultural industry structure upgrading is one of the important ways for AI to leverage its economic effect. Hence, improving the informatization level in the rural and agricultural sectors through multi-dimensionality is of positive and pragmatic significance for the rural economy.