When studying the environment assessment of recycling of used plastics products, the following two problems must be overcome; how to specify the environmental loads on the used plastics products under consideration, and how to assess the environment loads emitted on recovering and processing of used plastics products. In this paper, a new concept for the first problem is presented for the purpose of promoting recycling while a trial model relating environmental load emitted and recycle ratio are proposed for the second problem. Based on the concept and model, an environmental assessments of closed recycling of used PSP (polystyrene paper) trays to pellets, and of an open recycling of PET (polyethylene terephthalate) bottles to carpets are investigated.