Corona detection via spectral rang in Solar Blind Ultraviolet (SBUV) is an efficient method for power system maintenance. It is necessary to implement luminance calibration for SBUV detection system to ensure the test results’ reliability, including object luminance vs. gain control voltage and object luminance vs. gray level of the image. The calibrating system was established, which mainly consists of high stable deuterium lamp, integral ball and fiber optic spectrometer. A calibrated ultraviolet deuterium lamp which can be traced back to the American NIST was adopted to calibrate the fiber optic spectrometer, which was used as calibrated detector to calibrate the corona detection system. The relative curve between ICCD gain control voltage and system gain was fitted from the test results and the calibration equation of system was also given. Three experiments with different gain level were implemented to validate the equation. Test results show that the maxim luminance relative error between calculated value and measured value is 6.11% and the Root Mean Square (RMS) is 3.22% when ICCD works in its linear area. Analysis of the calibration scheme shows the uncertainty is 9.1%. It can satisfy the precision requirements of corona detection system. The response characteristics under deferent gain levels of detection system can also be used as a reference in designing auto-gain adjustment algorithm for corona detection.