This standard specifies a unified test method for determining the compressive (resistance to extrusion deformation) characteristics of gaskets under high-temperature conditions. It primarily involves applying different levels of stress to gasket specimens at a specific temperature (e.g., 150°C) and precisely measuring their thickness and deformation before and after compression, thereby evaluating the material's resistance to extrusion and yield stress. Conducting this test requires a testing machine capable of accurately controlling stress (with a maximum stress of 520 MPa), hardened pressure sleeves, and a heating furnace to ensure uniform heating of the specimens. This method provides a critical basis for evaluating the mechanical performance and quality control of various gasket materials under high-temperature operating conditions.