The supervision of grain reserves is a major event of national food security. China has built the largest grain internet of things in the world. Although there are still have some problems such as low data quality, low utilization rate, and serious information islands, it still provides a basis for conducting digital supervision on grain reserves. On the basis of studying the multi-fields coupling and biological theory in stored grain ecosystems, the author team proposed the continuity, periodicity and coordination principles of the digital supervision of grain reserves, and further proposed 7 intelligent strategies using the big data analysis of grain situation and the intelligent analysis method of 10 modes of grain storage in the granary. In combination with the application cases of 10 provinces that participated in the policy oriented inventory check of grain reserves organized in 2018, this paper analyzes the principle of digital supervision of grain reserves and 7 intelligent methods, which will accelerate the transformation and large-scale promotion of relevant technological achievements, and accelerating the construction of a high-quality technical system for grain reserves supervision. This digital intelligence method will promote the transformation of grain reserve management from “human management" to "technology management”, and let data play its due role in grain reserve decision-making and management.