To effectively solve the problems of the transient curing temperature field being out of control and the the malignant phenomenon of curing quality of the food being ruined during in granular food the continuous processing of granular food by using IR (infrared) linear source radiation, the rising temperature model of IR linear source radiation transient curing for granular food was built in this research to analyze its spatial change of irradiance. By means of numerical simulation software, the temperature field form characteristics of transient curing for different diameter granular food with different diameters under different radiation distances were investigated. The results show that the temperature field formation of IR linear source radiation transient curing for granular food depend closely on radiation intensity, particle size, and radiation distance,etc. The heat loss rate on the granular food surface and its change rate of internal energy correspond with the energy balance transient response, and the transient curing temperature field distribution in material reveals a decline along the direction of IR linear source radiation, and in the processing of litchi flesh with 4 mm particle diameter under 50 mm radiation distance, its curing temperature distribution is high and uniform. 