This standard specifies a test method for identifying the composition of recycled polypropylene (PP) plastics. It aims to provide a scientific approach to distinguish between post-consumer recycled PP plastics processed through physical recycling and virgin PP materials. The core of the standard involves using headspace gas chromatography-mass spectrometry (HS-GC-MS) to determine the volatile components of the materials and employing a random forest algorithm to construct a predictive model for material source identification. This method is primarily applicable to granular recycled PP materials produced through mechanical recycling processes, such as crushing, cleaning, and pelletizing. In practical applications, in addition to the methods specified in the standard, the industry often relies on instruments such as near-infrared spectrometers and Fourier-transform infrared spectrometers (FTIR) for rapid plastic type identification and quality control. The development of this standard helps standardize and improve the testing capabilities of the recycled plastics industry, supporting the advancement of the circular economy.