Abstract: In order to study the effect of packed material on corona discharge, the corona inception voltage,the average current of positive/negative DC corona discharge of needle-to-plate configuration are investigated under different conditions. The time-integrated images of positive/negative DC corona and positive pulsed corona are obtained and compared. The time-resolved images of positive pulsed corona discharge are captured to study the dynamics of the pulsed discharge. The effects of the size, the shape, the filling density and the permittivity of the dielectric particle on the positive pulsed corona discharge characteristics are also analyzed. The results show that the inception voltages of positive and negative DC coronas increase due to filling packed material. The positive corona discharge is apt to excite the surface discharge along the dielectric surface. And it is easier to form the surface discharge around smaller dielectric particles. In the positive pulsed corona discharge, the corona inception voltage decreases as the density and the permittivity of the dielectric material increase. The experimental results also show that the surface discharges are more easily formed with spherical packing material than with cylindrical material.