The filtered moiré deflection tomography is proposed to diagnose multi-component complex flow fields which contain chemical reactions. As an example, the combustion of propane is chosen as the measured field. The offset of moiré fringe is refined and transformed to deflection angle. The refractive-index distribution of field is reconstructed by deflection filtered back projection (DFBP), and the three-dimensional temperature and density distributions of a certain cross section at two different situations are given. By contrast, multi-component complex flow fields should not regard air as the studied object, chemical reaction and resultant of flow field must be considered , and the equivalent G-D constant and molecular weight of mixed flow field must be amended, according to specific conditions of the measured objects.