Objective To polish plating copper coatings by vertical impact electroplating device. Methods Glass ball, copper ball and lead ball were added to acid copper plating solution. Copper plating coatings with a thickness of 30 μm were prepared when the swing of the vertical impact electroplating device was 4 mm and its frequency was 12 Hz. Scanning electron microscopy (SEM) was used to observe the microstructure of the plating surface and study the effect of grinding media ball with different densities on unit cell size. The refinement mechanism mechanical grinding electroplating cell was studied by measuring the cathodic polarization degree in the process of mechanical polishing plating using potentiostat. The corrosion speed of plating in 3.5% NaCl solution of mass fraction was tested using gravity losing method to study the relationship between medium ball density and corrosion speed of copper plating. The relationship between medium ball density and corrosion speed of copper plating was verified employing electrochemical measurement technology. Results Compared with the ordinary coating, the crystal cells of mechanical polishing copper plating were smaller and the corrosion resistance was better. According to the test results, the crystal cells of mechanical polishing copper plating using lead ball were the smallest and the corrosion resistance was the best. The crystal cells of copper ball mechanical polishing copper plating and the corresponding corrosion resistance took the second place. The crystal cells of glass ball mechanical polishing copper plating were the largest and the corrosion resistance was the worst. Conclusion The smaller the copper plating cell was, the better corrosion resistance was as the density of medium ball increased in certain density range (2～12.3)×103 kg/m3.