The invention relates to the electromagnetic technology field and provides a radiation sensitivity test method and device under the reverberation chamber condition. The method comprises steps that interfered frequency of tested equipment and right angle components of field intensity at multiple stirring positions in a reverberation chamber are measured, according to the interfered frequency of the tested equipment and the right angle components, an interference probability and a parameter sigma are calculated; according to test frequency and dimensions of the tested equipment, a wave number and a radius of a smallest ball capable of containing the tested equipment are calculated, and a maximum directivity coefficient of the tested equipment is acquired according to the wave number and the radius; according to the parameter sigma, the interference frequency and the maximum directivity coefficient, critical radiation interference field intensity of the tested equipment can be acquired in combination with a preset model. The method is advantaged in that a problem of poor correlation between the radiation sensitivity test result of the tested equipment in the reverberation chamber and a uniform field is solved, the method is especially suitable for complex large-size equipment, and a new concept is provided for the radiation sensitivity test on the equipment under the reverberation chamber condition.