Vibrational temperature in circle discharge channel and central dot discharge channel of circle-dot filament in argon/air dielectric barrier discharge was firstly measured by using optical emission spectra. The variations of the vibrational temperature in central-dot discharge channel and circle discharge channel as a function of air content were also studied. Emission spectral lines of the N2 second positive band system (Ｃ ３Πｕ→Ｂ ３Πｇ) were used to calculate the vabrational temperature. It was found that the vibrational temperature of circle is higher than that of the central dot. The vibrational temperature of circle increases more rapidly than that of central dot although both increase with the increase in air content. These results are of great importance to the study of microdischarge in dielectric barrier discharge system.