This standard provides a unified product specification for the recycling of polyphenylene ether (PPE) engineering plastics, specifically targeting the mainstream pellet materials produced through mechanical recycling of waste polyphenylene ether/high-impact polystyrene alloy (PPE+PS-I) plastics in the market. It systematically defines the product classification, technical requirements, and comprehensive testing methods for such recycled plastics (PPE(REC)), aiming to ensure the quality of recycled materials and promote the green circular utilization of this heat-resistant, strong, and high-performance engineering plastic in high-end fields such as electronics, electrical appliances, and automotive industries. The required testing instruments are comprehensive, primarily including infrared spectrometers for qualitative analysis of the main materials, melt flow rate testers for measuring melt fluidity, and high-strength magnetic rods (not less than 6000 Gauss) for detecting metal impurities. Performance testing also involves tensile testing machines, impact testing machines, ash determination equipment, and more.