The discharge phenomena of moving water drop in a sphere-sphere DC gap are studied. Electric field strength distribution in the gap containing water drop is computed using the charge simulation method

getting the result that the field strength around the water drop is hoe times as high as that without water drops. The moving water drops can produce the corona discharge mud them and reduce the corona voltage and breakdown voltage. It is also contrasted that the water drops induce corona when the positive and negative voltages are respectively applied. It also provides the foundation for the water treatment by discharge plasma.