This paper optimizes the Wire-Electric Discharge Turning (EDT) process parameters for INCONEL 718 Nickel based super alloy via Taguchi-Grey Relation Analysis. The most significant factor has been identified through Analysis of Variance (ANOVA) technique; subsequently, rotational speed, pulse on time, pulse off time, servo voltage, wire feed rate, and flushing pressure have been chosen as input factors. Metal Removal Rate (MRR) and Surface Roughness (Ra) are considered as response characteristics; thus experiments are conducted according to L18 mixed type Taguchi's orthogonal array. Also the optimal process parameters are evaluated and the results of the confirmation test are validated. Experimental result shows that there is performance improvement by 3.588% and decrement by 9.171% of MRR and surface roughness, respectively. The ANOVA has shown that pulse on time has the most significant effect on MRR and Ra.