China is one of the countries with the largest grain output in the world. Therefore, it is of great significance to develop more intelligent and perfect grain drying tower for ensuring grain quality and promoting the development of agricultural technology. The main research contents of this paper include: using virtual instrument technology to realize the structure simulation and work process simulation of grain drying tower, and optimize the processing of it. PID temperature control is designed to realize automatic intelligent temperature regulation and emergency treatment during grain drying process. It can automatically raise temperature and lower temperature according to the relevant state value of grain in the granary. This system simulates the serial communication process of data, and analyzes the error of data.