This standard specifies a test method for determining the compressive properties at room temperature for carbon/carbon composites, particularly focusing on two common structures: three-dimensional piercing and quasi-three-dimensional needling. Its primary objective is to establish a unified testing protocol to obtain key mechanical performance data, such as compressive strength, compressive modulus of elasticity, and compressive stress-strain curves. As the core equipment supporting this test method, a universal material testing machine (or a specialized compression testing machine for composites) is utilized. The standard provides clear specifications for equipment accuracy, sample preparation requirements, and the loading method for uniaxial compression. The release of this standard effectively addresses the issue of significant result discrepancies in this material field caused by the lack of uniform testing methods.