In order to clarify the viscous flow transition process of shellac resin after heating and the change of its characteristic index after over viscous flow transition, and to determine the corresponding relationship between thermal hardening time and temperature of shellac resin, the viscous flow transition process of shellac resin was monitored by differential scanning calorimetry and heat table microscope observation method, and the thermodynamic parameters of viscous flow transition process were calculated. The changes of thermal hardening time, cold ethanol soluble matter and infrared spectrum after viscous flow transformation were measured, and the thermal hardening time at different temperatures was measured by the method of thermal hardening time of shellac resin, and the equation was fitted. The results show that the faster the heating rate is , the higher the peak temperature of the viscous flow transition of the shellac resin is, the lower the heat transfer efhciency of the molecule is , and the heat transfer will lag, and the viscous lac resinhas a smooth boundary and a water droplet shape. The relation equation between thermal hardening timeand temperature of shellac resin was obtained by fitting, and the significance test was carried out. it wasconcluded that the thermal hardening time of shellac resin decreased with the increase of heating tempera-ture. the trend decreases according to the exponential relation shown in the fitting equation.