Aiming at the problem of thermal damage layer on the surface after traditional short electric arc machining, the short electric arc–electrochemical hybrid machining of titanium alloy TC4 was studied, and the material removal mechanism of short electric arc-electrochemical hybrid machining was analyzed. The key parameters affecting the composite machining speed and surface quality were discussed through theoretical models. That is, the processing voltage, the resistivity of the working medium and the feed speed. The effects of key parameters on the surface quality of short electric arc–electrochemical hybrid machining were studied by single factor experiments. The experimental results show that the surface thermal damage layer after short electric arc machining can be well removed by using the electrochemical effect of the bottom surface gap. When the feed speed is 4 mm/min, the thermal damage layer can be completely removed. The machining efficiency is 354 mm3/min, and the surface roughness S_a is 17.982 μm.