The distribution of microdischarges in time and space , the influence of dielectric surface on microdischarges, and the characteristic of ozone generation were studied using electrical and optical methods . As a result, the phenomenon of a chain of microdischarges occurring in a brief period could be observed . In addition, it was found that the microdischarge characteristic, collective microdischarge phenomenon, and ozone yield varies according to the surface condition of the dielectric electrode. The ozone yield was high with a glass surface and low with a ceramic surface.