Abstract: Abstract: Most of the existing grain drying systems in the northeast of China are large and multistage tower-type coal drying systems, and in the process of grain drying, the system produces hot and humid exhaust gases directly into the atmosphere after a heat exchange of hot air and grain. It not only caused great waste of energy, but also seriously polluted the environment. Aiming at the characteristics of cold climate in northeast China and the problems of high energy consumption and high pollution of coal-fired corn drying system of the multi-stage tower type, a heat pipe combined with corn drying technology of multistage series heat pump is developed. This technology can realize the recovery of waste heat and exhaust impurities in the corn drying by burning coal in multistage tower-type, so as to achieve the effect of energy saving and emission reduction. On the basis of this technology, the series of 50 t/d, 150 t/d and 300 t/d of corn heat pump drying equipment are developed, and the industrialization demonstration of 3 kinds of scale has been carried out. The performance testing of 300 t/d corn heat pump drying system is carried out.. The results show that the power consumption of per hour is 538 kW. h, the dehumidification rate is 2016 kg/h, the heating coefficient COP of the heat pump is between 3.7-6.7, and the energy consumption ratio SMER of dehumidification is 3.75 kg/(kW·h). In the end , the economy between the heat pump drying of corn and the drying of corn by burning coal of the multi-stage tower are compared .The results show that cost of the heat pump drying to get one kilogram of dry corn is 0.038 yuan, while the cost of coal-fired drying is 0.049 yuan. The cost of heat pump drying of per unit of corn is 22.4% lower than the cost of the coal-fired drying. Compared with the drying of corn by coal, the heat pump drying of corn can greatly reduce pollutant emissions, and the effect of energy saving and emission reduction is obvious, which provides a valuable reference for the application of heat pump drying technology in the field of grain drying.