In the present study,a device of water electrodes was used to get different discharge modes in air and Ar respectively,including stochastic filament mode,hexagon pattern mode and homogeneous diffusion mode.By comparing the waveforms of light emission and current for the three different modes,the relationship between the waveforms of light emission and current in dielectric barrier discharge was investigated.Research results show that the waveforms of light emission and current are similar when the discharge signal is very strong.However,the discharge current signal can not be discerned from the displacement current when the discharge current is very weak,because the current signal includes discharge current and displacement current.Under this circumstance,discharge dynamics can be investigated by studying the waveform of light emission.In addition,the light emission signal of single filament was obtained because spatial resolved measurement can be easily realized for the light emission signal measurement.Consequently,the research results indicate that it is a good method to investigate the discharge dynamics by analyzing the waveform of light emission in dielectric barrier discharge.