During the retorting process of gas-heat carrier retort, the gas passes through the void generated by material pile-up and leads to pressure drop because of the effect of frictional drag.This study uses bulk-material-layer-resistance-loss-calculation-formula and Ergun equation to calculate the pressure drop of retort.The results are compared to the actual pressure drop.It is observed that these two methods conclude the theoretical values close to the actual ones,and that the trends for both two types of values are basically the same.Ergun is preferable for the operation of the project.