Abstract: The attribute identification of by-products and processed products of solid waste is the difficulty and focus of solid waste identification. A comparative study on the definitions of relevant by-products, co-products (uniformly called by-product substances), and products at home and abroad was conducted. The results indicated that the characteristics of by-product substances included the following points: unintentionally obtained material, lacking precise quantity control, needing further processing to meet market demands, and generating quantities that were not controlled by market demands. After summarizing the main standards for identifying by-products in current regulations in China and the problems that arose, the following main points were proposed: the by-products identified as non-solid waste should be considered as co-products, and their intended use should be clearly defined and should not be used for any other purpose. Based on the above viewpoints, revision suggestions on the identification of co-products in Identification Standards for Solid Wastes - General Principles (GB 34330-2017) were proposed, aiming to provide reference for solid waste management of production enterprises and administrative departments.