The invention relates to a granary capacity real-time monitoring system, and belongs to field of grain storage amount monitoring. According to the technical scheme, the granary capacity real-time monitoring system comprises a sensing sub-system, a measuring sub-system, a controlling sub-system and a computing sub-system. The sensing sub-system comprises a pressure sensor, a signal transmission line, a digital voltmeter and a power supplying unit. The measuring sub-system comprises a measuring device, a signal transmission line and a power supplying unit. The controlling sub-system comprises a controlling unit, a switchboard, a communication module and a power supplying unit. The computing sub-system comprises a data receiving unit, a data processing unit and a data displaying unit. The sensing sub-system senses change of grain stack states in real time, the measuring sub-system collects grain face information in a granary, the controlling sub-system controls the sensing sub-system and the measuring sub-system and conducts storage and management on the data collected by the sensing sub-system and the measuring sub-system, and the computing sub-system conducts processing on the storage data of the controlling sub-system and then obtains real-time granary capacity. The granary capacity real-time monitoring system has the advantages of being capable of conducting remote intelligent control, high in measuring precision, high in reliability, good in stability and durability, resistant to dust and corrosion and the like. Furthermore, the granary capacity real-time monitoring system is convenient to popularize and apply.