Abstract The compound machining (CM) compounded with electrical discharge machining (EDM) and arc machining is a novel approach to process difficult-to-machine materials especially for the aerospace materials such as Inconel718. An exciting material removal rate (MRR) and a small diameter of overcut (DOC) can be received in this approach. A suitable selection of machining parameters plays a key role in CM of Inconel718. Therefore, a various machining parameters affecting MRR and DOC such as peak current, electrode rotation speed and peak voltage were analyzed. This paper highlights the combined influence of these parameters in CM. A 2 3 factorial with central composite design (CCD) and a total of 20 experiments were conducted in this study. The mathematical model of objective function between the machining parameters and the dependent variable was obtained by utilizing the response surface method (RSM). Finally, the optimized machining parameters can be acquired in CM of Inconel718.