Redesign is a widespread strategy for product improvement whose essence is the optimization of design parameters (DPs) considering the trade-off between customer satisfaction and cost concerns. Similar to the relation between customer requirements (CRs) and customer satisfaction, the sensitivity of customer satisfaction is diverse to different DPs. In this study, a sensitivity-enhanced customer satisfaction function is defined for redesign model construction. This fills the research gap in product redesign that lacking of consideration and quantification of customer satisfaction sensitivity. First, a sensitivity index is defined based on Kano indices for analyzing sensitivity of customer satisfaction in different DP categories. Second, traditional customer satisfaction function has been improved by injecting the sensitivity of customer satisfaction to the variations of DPs. Subsequently, a DP optimization model is established to maximize shared surplus between customers and enterprise. Finally, a case study involving the redesign of a braking system of automobile is implemented to demonstrate the effectiveness and rationality of the proposed approach. The results show that the improved customer satisfaction function can reflect a more nuanced relationship between customer satisfaction and fulfilment level of DPs. Additionally, the proposed redesign model helps designers determine the target values of DPs under a better trade-off and enhances enterprise competitiveness.