GB/T 24633.1-2009 is the basic part of the cylindricity specification. It systematically sorts out the related vocabulary of cylindricity, clearly defines the professional terms such as cylindricity error, cylindrical elements, etc., to prevent communication ambiguity. At the same time, it is clear to describe the key parameters of cylindricity, such as shape parameters, position parameters, etc., and standardize its value range and calculation method. Provide a unified language and quantitative basis for the subsequent measurement, evaluation and application of cylindricity, help various industries to accurately grasp the concept of cylindricity, and ensure product mass.