Abstract: The study on the sensitivity testing technique for the computed radiography(CR) is conducted with a specially-designed testing block. A large number of experiments have shown that the testing block can well verify the difference between the CR displaying of object details and determine the effect of various CR parameters on the sensitivity of CR images. Moreover, the sensitivity tests are performed respectively by using the image quality indicator(IQI) of the hole type, the wire type and the double wire type, as well as the testing block. The results show that the sensitivity distinguishing ability of the testing block is superior to that of the above mentioned IQIs.