CO2-CH4 reforming by non-equilibrium plasma to syngas is an important emerging technology pathway to realize the resource utilization for the two greenhouse gases. The reaction pathway of CO2-CH4 reforming by non-thermal plasma in a dielectric barrier discharge (DBD) reactor at ambient temperature and pressure was thoroughly investigated by combing emission spectrometry analysis, reaction kinetics simulation and continuous mass spectrometry measurements. A maximum conversion of CH4 and CO2 of 25.8% and 9.6% respectively, can be achieved under a specific energy input (SEI) of 52 J/cm3. The continuous mass spectrometry online analysis of the stable gaseous products shows that C2H4 acts as a key intermediate in the formation of C2 hydrocarbons. The higher the proportion of CH4, the greater the generation of C2 hydrocarbons, and it increases in the order of C2H6<C2H4<C2H2.·CH, ·C2 radicals and characteristic spectral lines of CO and CO+2 are detected in the emission spectrum. The relative intensity of ·CH decreases significantly with the increase of specific power, and the relative intensity of CO+2 changes little. The generation and consumption pathways of C2 and C3 products are analyzed by kinetic calculation, and it is found that 89.2% of C2H6 comes from the combination reaction CH3+CH3(+M)C2H6(+M), 78.9% of C2H4 is mainly formed by CH4+CHC2H4+H and C2H3+H(+M)C2H4(+M) reaction, 61.1% of C2H2 is formed by electron collision reaction, and the formation of C2 product follows the path: CH4→C2H6→C2H4→C2H2. The reaction of electron collision dissociation e+CO2CO+O-of CO2 is an  important formation pathway of CO, while the reaction CH3+CH4C2H+5+H2 and electron collision dissociation of CH4 are the key generation pathway of H2. Integration of emission spectroscopy and kinetic calculation provides a useful tool to uncover the reaction mechanism of plasma-enhanced CO2-CH4 reforming process.