The CCD (Charge-coupled device) image sensor can invert the surface temperature of the object by collecting the radiation signal of the high-temperature object. It is a non-contact temperature measurement method, which has the characteristics of fast response without affecting the surface distribution of the tested object. Due to the restriction of the development level of CCD, the exposure tolerance of imaging is low. As a result, the temperature field measurement range is low. In order to solve the problem of low exposure tolerance caused by dark current and saturation in CCD, this paper proposes a radiation temperature measuring method with high dynamic range via fast double-exposure image fusion technology, and a high temperature field measurement system based on LabVIEW and visible light industrial camera is developed. The method proposed in this study is suitable for the stationary objects in temperature range from 750 to 1200 ℃. By correcting the non-impulse response of the sensor, the temperature measurement error is better than 2%. By fusing two images with different exposure duration, the dynamic temperature measurement range is increased to 59.2%, which significantly improves the adaptability of the CCD in the measurement of high temperature field.