In temperature measurement with near-infrared colorimetry method, when the environment radiation intensity in furnace is higher than that of work piece being detected, accuracy of measurement is influenced by environment radiation significantly. In order to obtain more reliable results, according to measurement analysis, the relationship was obtained between projected absorption rate of radiation, reflectivity and transmittance of the work piece detected in different temperature fields, which supplies theory basis for measuring the real temperature of work piece accurately. Furthermore, a novel resolution to eliminate background radiation in high temperature is proposed based on the results.