GB/T 42087-2022 specifies the cleaning procedures and cleanliness inspection methods for hydraulic transmission systems. It specifies the preparation before cleaning, such as system evaluation, cleaning liquid selection. Detail the cleaning process, including the operation points and time control of cycle cleaning and immersion cleaning. Specify the cleanliness inspection methods, covering the collection and analysis methods of pollutants, and the determination of cleanliness grades based on indicators such as particle counts. Following this standard can effectively clean the hydraulic transmission system, accurately inspect the cleanliness, prevent system failures caused by pollution, ensure stable and efficient operation of the system, and prolong the service life of the equipment.