A stable micro-discharge channel（filament）in air discharge is obtained by discharge cleaning method in a dielectric barrier discharge system with two water electrodes. The distributions of intensity of luminescence and the vibrational temperature of a single micro-discharge filament are measured from instantaneous anode to instantaneous cathode. It is found that the emission intensity of discharge filament presents a distribution like a goblet with base locating at instantaneous cathode in each half period of the applied voltage. The vibrational temperature reaches the maximum at the middle of gap of the two parallel electrodes and is the minimum at the instantaneous anode.