Real-time measurement of temperature field can be achieved by colorimetric method using ICCD as sen-sor. However, due to limited dynamic response range of the ICCD, the measurable range of temperature is very small. In order to expand the temperature measuring range, a device was developed which can take several two-color images with different shutoff times subsequently within very short time. First, the principle of real-time measurement of tem-perature field with two-color thermal images is introduced. Then theoretical analysis on this method, including deter-mination of various parameters, such as shutoff time, number of temperature range, wavelength of the colors, etc. is described. Experiments were conducted, which proved that theoretical analysis coincides with the experimental re-sults.