To utilize resources efficiently, realizing closed-loop manufacturing becomes a crucial issue. This paper proposes a design support method for a product life cycle in order to circulate resources efficiently by means of recycling, reuse, remanufacturing, and so forth. Our previous work has proposed a design object model, which represents a product life cycle from the viewpoint of both its nominal information and entity information. This study refers to a specific state of an individual product as ‘entity information,’ as opposed to ‘nominal information,’ which represents design information specified by designers. The method proposed in this paper extracts design parameters to be modified from the nominal information to achieve a design requirement by analyzing relationship of the parameters of the product and its life cycle flow described in the design object model. The method conducts sensitivity analysis on the extracted design parameters in order to identify a design parameter effective to achieve the design requirement. A case study on a product life cycle of a smart phone is illustrated for demonstrating the feasibility of the proposed method.