|Two-color radiation thermometry is a non-contact method that can be applied to measure the temperature of the burden surface of the blast furnace for pig iron production in order to reduce operating costs and ensuring safety. In this method the burden surface is measured based on the ratio of the thermal intensity at two different spectral bands. e.g. short wavelength (SW) and long wavelength (LW). However, above burden zone is a harsh environment with high temperature, dust, hot gases and high pressure. In such conditions, the thermal radiation emitted by the burden surface can be scattered and absorbed by the constituents of the measurement environment, resulting in a different transmittance, τ, for the SW and LW bands and thus leading to a significant error in the measured temperature. This method was developed to determine the transmittance of the SW and LW band through the path between the burden surface and the twocolor probe.