Ensuring the quantitative safety of agricultural product supply is the security bottom line for building a new development pattern and the development of agricultural insurance offers new possibilities for this purpose. It is important to explore the impacts of agricultural insurance on the quantitative safety of agricultural product supply in order to promote the construction of a strong agricultural country and the structural reform of the supply side of agricultural products. Based on a panel data of the Central Economic Zone from 2008 to 2020, this paper examined the dynamic evolution trend of agricultural insurance and the quantitative safety of agricultural product supply by the Kernel density estimation method and analyzed the effects and mechanism of agricultural insurance on the quantitative safety of agricultural product supply by the fixed-effect model and the mediating-effect model. Results show that the development level of agricultural insurance and the quantitative safety of agricultural product supply in the Central Economic Zone shows a fluctuating growth trend with obvious regional differences. The development levels of agricultural insurance and the quantitative safety of agricultural product supply in Heilongjiang, Henan, and Anhui were significantly better than those in Shanxi and Jiangxi. The finding that agricultural insurance effectively enhances the quantitative safety of agricultural product supply passes endogeneity and robustness tests by the winsorize and instrumental variable approaches. Further analysis indicates that agricultural insurance improves the agricultural total factor productivity, which in turn improves the quantitative safety of agricultural product supply. Therefore, to ensure the effective supply of agricultural products, this paper suggests: promoting the high-quality development of agricultural insurance, relying on agricultural insurance to guide the flow of production factors to agriculture, and promoting innovation in agricultural insurance risk management service models.