In present book, Modeling and optimization technique is used on Duplex turning parameters to model the input parameters such as cutting speed, feed rate primary and secondary depth of cut with the responses surface roughness, primary cutting force and secondary cutting force. Further, the optimization technique is used to get the optimal level of input parameters.For modeling the input parameters Response surface Methodology (RSM) technique is used. For optimization optimal level of Taguchi methodology (TM) is used in RSM and D-optimality test is performed for optimization of input parameters. Grey relational analysis (GRA) is also used to optimize multi-response parameters to get the optimal parameter level.