The properties of polymer material can be shaped by crystallinity distribution during the film extrusion process. This paper addresses the implementation of design sensitivity analysis to determine the process inputs which can generate the desired crystallinity distribution. To achieve such a goal, the performance index is defined in terms of the difference between the desired and the actual crystallinity distributions. The sensitivity of the performance index to process inputs is determined in order to update these process inputs in every iteration of optimization. The design sensitivity analysis presented here allows a systematic movement through the search space to reach a sub-optimal set of process inputs. the simulation results show that the proposed methodology can determine the process inputs in order to generate the crystallinity distribution close to the desired one.