This document specifies the quality characteristics indicators and classification requirements, inspection methods, sampling plans and quality grade assessment methods for aluminum piston products for reciprocating internal combustion engines with a cylinder diameter less than or equal to 200mm. This document is suitable for grading and evaluating the quality of aluminum piston products for reciprocating internal combustion engines. Aluminum pistons for other uses can also be implemented with reference. For the rest of the technical content, see the standard text.