The utility model provides an auxiliary electrode cap sharpening machine which comprises a supporting mechanism, a clamping and withdrawing mechanism used for clamping an electrode cap, a grinding mechanism used for grinding the electrode cap on the clamping and withdrawing mechanism, a pushing mechanism used for driving the clamping and withdrawing mechanism to move towards the grinding mechanism, a protective mechanism and a collecting mechanism, wherein the pushing mechanism comprises a guide rail fixed on a supporting base, a connecting board installed on the guide rail in a sliding mode and used for driving the clamping and withdrawing mechanism to move, and a moving part driving the connecting board to move on the guide rail, the grinding mechanism comprises a grinding support fixed on the supporting base, a sharpening tool bit is fixed on the front lateral side of the grinding support in a rotary mode, and the front lateral side of the grinding support is perpendicular to the guide rail. The auxiliary electrode cap sharpening machine has the advantages that the structure is simple, installation and maintenance are simple, convenient and fast, the pushing mechanism and the grinding mechanism are matched closely, grinding efficiency is greatly improved compared with that of a traditional grinding method achieved with a hanging type spot-welder, and manual labor is greatly saved due to the fact that operation can be achieved by a single person.