A new method is proposed for simultaneous reconstruction of three-dimensional particle temperature, particle concentration, and H2O concentration distributions of axisymmetric flames using multi-spectral flame images. The multi-spectral flame images are obtained by cameras, each of which is equipped with one of three filters whose center wavelength is 700 nm, 900 nm, and 950 nm. The absorption of H2O is considered to be represented solely by the monochromatic image obtained at a wavelength of 950 nm, whereas the thermal radiation of particles is assumed to be represented by all three monochromatic flame images. For a signal-to-noise ratio value greater than 70 dB, the temperature and concentration distributions were reconstructed accurately. The experiment results indicate the particle temperature, particle concentration, and H2O concentration are low in the inner cone of the flame and they are high in the outer cone of the flame. The maximum difference between the temperature calculated from the flame images and the temperature measured by the thermocouple is 5%.