Dynamic monitoring technology of grain inventory quantity has become a new technical demand of grain storage management. On the basis of the current situation of static monitoring technology of grain stock quantity, the difficulties of dynamic monitoring technology were analyzed and put forward. This paper mainly introduced the research progress and application of dynamic inventory quantity monitoring in the development of three-dimensional measuring device, data acquisition and fusion technology of multi- measuring stations of super large grain piles, high precision volume algorithm of irregular grain piles, average density evaluation method of complex heterogeneous grain piles, integrated management software platform and so on. The measurement error of the developed dynamic monitoring system for grain inventory quantity was less than 2%, which meet the application requirements. This new technology provides the technical support for the information management and digital transformation development of grain storage business.