To increase the efficiency of EDM (electrical discharge machining), this paper proposed a function electrode which could inject water and oxygen with high pressure into the machining area, while the chemical energy produced by the reaction of the metal with oxygen was used to remove the metal material in addition EDM. The experiments of the normal EDM with cylindrical electrode and the EDM-induced ablation machining with function electrode to die steel Cr12 were conducted and the influencing law of  electric  and nonelectric parameters on the EDMinduced ablation machining was  studied. The results show that the processing efficiency of positive polarity ablation machining on die steel Cr12 is 178.12 mm3/min which is 20.2 times compared with the normal EDM under the same condition, and the polarity effect is obvious. The MRR (material removal rate) of ablation machining increases approximately linearly with ton and I. With the increase of η which is the ratio of pneumatic and hydraulic, the MRR increases first and then decreases. And with the increase of electrode speed n, the MRR increases first and then decrease slightly.