Abstract: In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cables relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process.