The platinum pin-type grading electrodes are widely installed in the practical high voltage converter valve cooling system to limit the leakage current between the cooling water pipe and metallic heat sink. Then the deposited products on the grading electrodes fall off easily and probably result in water pipe blockage. Therefore a new design of ring-type grading electrode is proposed to replace the traditional pin-type grading electrode in this paper. The simulation deposition tests are carried out in the laboratery between the ring-type grading electrode and pin-type grading electrode. The distribution characteristics of deposited products on the two types of grading electrodes are analyzed contrastively. The test results show that the ring-type grading electrodes will effectively reduce the deposition rate to one tenth of the pin-type electrodes, and then lower the probability of falling off of deposition produt. Besides, the ring-type grading electrodes can eliminate the electric potential difference between the two ends of the tributary cooling water pipe, thus further inhibit the corrosion of metallic heat sinks led by the leakage current.