For the above 2 000 K temperature field, due to the saturation problem of thermal imager, the reconstruction of thermal imager temperature field of this measurement method is no longer applicable. Using a plurality of optical probe and through the optical fiber transmission, data measurements were realized under the multi-channels and multi-spectral. On the basis of the proposed model without the assumption of the relationship between the emissivity and wavelength, the true temperature of the surface was obtained by the iterative algorithm. By arranging a cross temperature structure of the multi spectral method to the turbocharged boiler, multi-points temperature measurement were achieved and the temperature distribution of the temperature field was constructed. The results show the method can be used to measure the temperature field distribution of the turbocharged boiler and the prediction error is small, which can be used as a reference for the analysis and diagnosis of high temperature field.