In inertial confinement fusion(ICF) laser facility, accurate measurement of the gain uniformity of disk amplifiers is the basis for device design. Based on CCD imaging method, the gain uniformity of disk amplifiers with the average small\|signal gain coefficient is measured about 5.28%/cm on integration\|test\|bed(ITB) laser facility, which is the first laser facility with ten thousand joules output in single beam. Experimental results show that when the average small\|signal gain coefficient is 5.28%/cm, the gain uniformity is 1.091 (maximum /average) within the aperture range, and within the range of 360 mm×360 mm laser beam, the gain uniformity is about 1.061 (maximum/average), which satisfied the 19.6 kJ/5 ns laser output on ITB laser facility.