An inverse radiation analysis is presented for simultaneous reconstruction of temperature and volume fraction fields of soot and metal-oxide nanoparticles in a nanofluid fuel sooting flame from the knowledge of the line-of-sight spectral radiation emission. The inverse problem is formulated as a linear optimization problem, which was successfully solved by the least-square QR decomposition method. The effects of ray number, wavelength combination and measurement error on the reconstruction accuracy were investigated. The results show that the temperature, volume fraction fields of soot and metal-oxide nanoparticles can be reconstructed accurately for the exact and noisy data. (C) 2017 Elsevier Ltd. All rights reserved.