An environmental impact estimation method comprising storing information related to reuse and recycle objects in a memory unit, performing life cycle modeling to make a life cycle model, the life cycle modeling including reading information related to the reuse and recycle objects, selecting some of the reuse and recycle objects which can be diverted to a new product, and combining the reuse and recycle objects selected together to assemble new product, predicting, as a superposition of two or more arbitrary shapes, recovery distribution of products by the life cycle modeling to predict a recovery quantity of the reuse and recycle objected, using the life cycle model, determining the arbitrary shapes as a peak of the product worth life or product useful life, and evaluating an environmental impact and a cost to bear in reuse or recycle based on prediction result.