To improve the accuracy of temperature measurement using CCD image, for the selection of the wavelength impacts the result of the temperature measurement greatly, an improved colorimetric temperature measurement method is proposed, which is independent of the spectroscopic characteristics and the representative wavelengths of the CCD. Using the relationship between color and temperature, three solutions of temperature are obtained, and the temperature value based on the correlation of those temperatures is optimized. Then the optimum temperature is obtained. The improved method not only avoids the measurement errors caused by the wavelength selection, but also makes the calculated values closer to the true value. The experimental results show that, compared with the traditional method, the measurement error of the improved colorimetric temperature measurement method is decreased by 1.16%, and the accuracy and practicality of colorimetric temperature measurement are improved.