The work aims to obtain high surface quality of TC4 titanium alloy by means of mixed powder electrical discharge machining method with red copper and graphite as tool electrodes. The roughness of the workpiece surface was measured by handheld TR200 roughness tester, surface morphology and phase structure were analyzed by using scanning electron microscope (SEM) and X-ray diffraction, and micro hardness of the workpiece was measured by using FM800 micro hardness tester. Provided with the same electrical parameters, the surface roughness and hardness of the workpiece treated with red copper electrode was lower than that treated with graphite electrode. Provided that I=4.5 A and tON=30 ?s, the average roughness values of the surfaces treated with red copper and graphite electrodes were 2.223 μm and 2.796 μm respectively, while the surface hardness values were 600HV and 700HV respectively. Provided that I=9 A and tON=30 ?s, the average roughness values of the surface treated with red copper and graphite electrodes were 2.748 μm and 3.705 μm respectively, while the surface hardness values were 650HV and 750HV respectively. Under different electrode conditions, the surfaces of TC4 titanium alloy workpieces machined by powder mixed EDM are all strengthened.