As we know, it is a useful method to prolong cupping mould lifecycle by employing diamond as cupping mould, especially to cupping mould of cupping horniness material. However, the machining of diamond cupping mould is always difficult. The paper intends to use the method of ultrasonic and electric spark combined to process diamond cupping mould. Based on the theory research and experiment, a satisfied result is attained. The experiment proves that the method is feasible, which decreases not only the chances of short-circuit in the process but also the energy consumption and improves machining efficiency significantly. These advantages are obvious.