Obtaining the mechanical response of CuCrZr alloy under coupled electro-magnetic-thermal-mechanical loading is significant for the engineering application of CuCrZr alloy, which is one of the candidate materials for electromagnetic railgun rails. This paper proposes an external-magnetic-field-assisted electromagnetic expanding ring technique, which stably achieves high strain rate loading exceeding 10⁴ s^–1 without the significant increase in the induced current and Joule heating temperature rise in the metal sample ring. Based on this technique, a study on the dynamic tensile properties of CuCrZr alloy under coupled electro-magnetic-thermal-mechanical loading was conducted. The stress-strain curves and fracture strain of CuCrZr alloy under conditions of high current density, high strain rate, high temperature rise rate, and strong magnetic field were obtained. The results provide important references for the application of CuCrZr alloy under multi-physics field coupling conditions.