The effects of introduced supporting electrolyte on the galvanic deposition of Cu2O crystals have been investigated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD). The results show that the chemical nature of supporting electrolytes plays very important roles in the galvanic deposition of Cu2O crystals. The chloride stabilizes the (100) planes of Cu2O crystals, resulting in the formation of cubic crystals, while nitrate, sulfate and fluoride stabilize the (111) planes of Cu2O crystals, leading to the deposition of truncated octahedral and octahedral Cu2O crystals. It provides a facile way to control the morphology of galvanically obtained Cu2O crystals by indirectly adjusting the inorganic adsorption agents.