This document specifies the principles, specimens, test equipment, test procedures, data processing analysis and test reports of axial-torsional composite fatigue testing of metal materials under strain control. This document is applicable to axial-torsional composite fatigue tests in which metal thin-walled tube specimens are subjected to loading waveforms with constant amplitude symmetry and zero average strain at room temperature and high temperature, and axial and torsional waveforms with the same frequency.