A hand-held grain inspection system which is suitable for small granary was researched. Unlike traditional large temperature measuring system, the hand-held grain inspection system can detect the temperature and humidity inside of the small granary directly by insert the sensor into the grain heap. The system interface can set agilely the threshold of temperature and humidity and alarm automatically. And it has the function of controlling the fan starting and stopping for emergency, which can be operated according to the measured temperature and humidity. The system has the characteristics of high accuracy, small in size, low cost and convenient operation. It not only meets the needs of the future development of grain service system, but also greatly meets the needs of farmers. It will have great application prospects in grain industry in the future.