GB/T 43938.2-2024 is the second part of a series of standards for testing the mechanical properties of thin-walled carbon fiber reinforced composite tubes. It specifies the test requirements for axial compression performance and applies to such tubes with a wall thickness not exceeding 1 mm and a nominal diameter less than 50 mm. The core measurements include axial compressive strength and elastic modulus. The standard clarifies specimen preparation, environmental conditions, and loading procedures, employing inner and outer sleeves bonded to the specimen to avoid clamping damage. The test requires a compression testing machine with a relative load error not exceeding ±1%, deformation measurement instruments with a relative error ≤0.5%, and measuring tools with an accuracy of 0.01 mm. This provides a unified technical basis for material research, development, and quality control in fields such as aerospace.