The demand for high surface finish in hard to cut materials with complex profiles are recently increasing by increase of design modifications, new product geometries, etc. Wire cut Electrical Discharge Machining is kind of unconventional machining process generally employed for meeting such requirements. The materials which withstand its mechanical properties even it exposed to extremely high temperature are preferred for aerospace. An austenitic alloy 12X18H10T - Stainless Steel is such kind of material which utilized in aerospace at elevated temperature. This study aims to examine maximize surface quality of WEDM of 12X18H10T - Stainless Steel and establish a mathematical model to predict the response in by means of input parameters. This investigation utilized the Taguchi L9 experiential Design with factors of Pulse off Time, Wire Tension, Pulse on Time, and Wire Feed Rate. A constant machining time the effects of above four parameters on surface quality was investigated and optimized parameters for best surface quality.