Taking the physical model of a small oil-shale retorting furnace with gas heat carrier as research object, a quasi homogeneous mathematical model was established to simulate the process of heating the pebbles in the porous zone and was solved by Fluent, a commercial CFD software. We compared the calculated results of temperature with the measured data, and analyzes the cause of the deviation between them.The result showed that the calculated value is relatively close to the measured data(the relative error is 6.85%) and the model can predict accurately the actual temperature field. The research results can provide support for the process of structural design of the large oil-shale retorting furnace with gas heat carrier.