Abstract: An improved two-color pyrometer for measuring surface temperature ranging from 600℃ to 1200℃ is developed. A gold-plated semispherical reflector is placed ahead of a two-color pyrometer. When the reflector is positioned facing the measured target， the received radiance energies are increased， and the disparity between the effective emissivities of the two received wavelengths is decreased. As a result， the measurement error of the two-color pyrometer is reduced，compared with the one without a reflector. The expression of effective emissivity for the focused reflector is deduced. A fast measurement apparatus is developed， which spends 0.7s on one time of measurement， in order to prevent temperature disturbance. A plain-type thermocouple is made， and the proposed pyrometer measures the surface temperature of the thermocouple for validation. The measurement error is within 1.1℃.

Key words: reflector, two-color pyrometer, surface temperature, temperature measurement, emissivity