The invention provides a test device for testing the radiation sensitivity of an electric field and a test method thereof. The test device comprises a main control computer, a PCI (Personal Communication Interface)-GPIB (General Purpose Interface Bus) control card, a signal generator, a switch array, a power amplifier A, a power amplifier B, a coupler A, a coupler B, a power meter, an antenna A,an antenna B, a field intensity probe and a field intensity monitor. The test device solves the problem of serious attenuation of radio-frequency signals of a 10kHZ-40GHz frequency range signal generator during remote transmission based on different transmission characteristics of radio frequency signals at high and low frequency bands. When equipment under test abnormally works during the automatic control test process, the test method can be immediately switched to the radiation sensitivity manual test of the electric field; and after the normality is restored, the manual test is switched back to the automatic test, so as to continuously test till the whole test process is finished. The test device is convenient and flexible to operate and has high safety and reliability.