Based on the theory of radiometry, the measurement technique for linear response of ultraviolet ICCD (UV-ICCD) detector was studied and a comparative measurement method was presented. The surface of photocathode in the UV-ICCD was set in the same section with the end of fiber belonging to the reference detector. Firstly, the attenuation of irradiance was measured via reference detector. Then, UV-ICCD was set in center of the irradiance field. The outputs of UV-ICCD were recorded according to the corresponding irradiance at that time. At last, relationship curve between output gray value of UV-ICCD and input irradiance was given. Scientific-grade spectrometer with low non-linearity, which was less than 0.2%, was adopted in this project because the accuracy of the measure results depends on the accuracy of the spectrometer. Measurement instrument consists of standard deuterium lamp with high stabilization, optics-attenuator, integrating sphere, reference detector and computer. Auto control is realized via special software during the test. Experimental results show that non-linearity of UV-ICCD is less than 3%, and the uncertainty of comparison measurement method is less than 5%.