Minimizing environmental loads and costs throughout a product's lifecycle requires appropriate lifecycle design in addition to the design of the product itself. Design of a lifecycle of a product involves planning lifecycle strategies, evaluating it from various viewpoints and optimizing the overall picture based on the item's properties. A product's lifecycle strategy can be designed easily by describing lifecycle scenarios at an early stage and the product architecture should match the desired one. In evaluating product structure, we must take into account the applicability of scenarios to the designed product. We should derive plausible product structure implementing an executable lifecycle scenario under the equilibrium between its process costs and reduction effects on the environmental loads by executing the scenario. In order to include this aspect, we formalize the probability that each component will follow the preferable lifecycle paths designated by the scenario. We also propose an index for evaluating and improving efficiency in resource circulation of the designed product structure.