Abstract: Cyclic steam stimulation is one key technology for thermal production of heavy oil, and the quantitative calculation of spatial distribution and dynamic change of steam chamber is of great significance to the oil production. In order to figure out the spatial distribution of steam chamber, a soaking temperature drop model was established based on the theoretical analysis of thermal conduction to analyze the steam absorption profile of steam huff and puff well. Then, the initial size and distribution of steam chamber were calculated by means of least square algorithm. Finally, the calculation result was compared with the data acquired from the actual well. It is shown that the calculation result is in accordance with the measurement value, indicating the feasibility and reliability of this interpretation model. By virtue of this model, the size and distribution of steam chamber in the process of thermal production can be understood in detail, so as to provide the reference for the SAGD parameters, e.g., total steam injection and steam injection time. In addition, the parameter sensitivity analysis on this model shows that thermal diffusion coefficient, thickness, initial temperature and steam temperature have more effects on the calculation results, so their valuing in actual application shall be focused.