Plasma processing of a (CH4( )+ CO2) mixture can lead to the formation of synthesis gas (CO + H-2). The use of a nonthermal plasma for this type of process seems very promising. We report here an electric and spectroscopic characteristic of plasma created in a (CH4 + CO2) mixture by a high-voltage, steep front-voltage (>10(12) V/s), very-short-pulse triggered dielectric barrier discharge in a tubular cell. Particular attention was payed to the determination of the rotational temperature for C-2. Time resolved investigation of the Swan band leads to an estimated value around 3000 K.