At room temperature, if there were many objects with different temperature and different emissivity in the same environment, it is difficult to get all the objects’ temperature field at the same time by the single band radiation method. Even if the emissivity data can be obtained, the matching problem between the objects and the picture still need to be solved. In the view of the problems, the dual-band colorimetric method was applied. The important optical parameters for this method were analyzed based on the temperature resolution and the simulation of temperature field imaging showed that the dual-band method can eliminate the influence of the emissivity on the temperature imaging and distinguish the temperature information of the objects with different emissivity at room temperature.