This paper is a study on Perovskite Solar Cell to optimize open circuit voltage, Vocand short circuit current density, Jscfor maximum efficiency at variation depth of interface defect layer (IDL). The Perovskite Solar Cell structure is simulated with combinations of IDL at 6nm, 8nm and 10nm of thickness sandwiches on both side of the solar cell absorber layer. Taguchi Method using L9 Orthogonal Array with Larger-The-Better (LTB) was used on finding most effective value on three material parameters: Cadmium Sulfide (CdS) as an electron transport layer (ETL), Perovskite absorber layer (CH3NH3Pbl3) and Copper Telluride (CuTe) as hole transport layer (HTL) in order to achieved best Voc and Jscvalues. The works was done by simulating a numerical model using Analysis Of Microelectronic and Photonic Structures (AMPS-ID) software. Using ANOVA, it was discovered the Perovskite absorber layer thickness is vital in affecting the increasing and decreasing on both Vocand Jsc. Taguchi predicted a 200nm of thickness for best Jsc but predicted 300nm for best Voc. The thickness of 200nm is selected for cost effectiveness. Taguchi method also predicted CdS and CuTe are considered slightly significant on improving the efficiency. Post Taguchi optimization approach shows Perovskite Solar Cell with CH3NH3Pbl3absorber layer has average power conversion efficiency of 20.7% on any combination of mentioned IDL thickness. With the aid of Taguchi method, a stable Perovskite Solar Cell efficiency with variation IDL thickness is achieved.