Abstract: In lowlightlevel(LLL) imageintensified charge coulped device (ICCD) parameters measurement, in order to obtain the testing parameters such as the resolution, the signaltonoise ratio, the minimum intensity of illumination and the image plane uniformity, the integral ball weak diffuse light system with wide dynamic range is required. Through analyzing the structure and limitation of the traditional light source, and according to the different requirements for the light intensity of illumination in LLL ICCD synthetic parameter tests, a wide dynamic range diffuse light system was designed. The light source system utilized the doubleintegral ball mode, and through using the wedge gradient variable aperture diaphragm and implementation, the continuous changing of illumination under the constant color temperature was realized, and the uniform diffuse light source with different intensities of illumination ranges was formated. Furthermore,the weak light illumination output range and uniformity of LLL ICCD parameter calibrating device were measured. Results show that the emergent light illumination range of the light source is 10-7lx～103 lx,the emergent light uniformity is 98%, the light source is suitable for measuring the LLL ICCD performance parameters.