Photocathode detection system of X-ray streak camera was developed for the rapid calibration and detection of the cathode in laser inertia confinement fusion. Through the design of the trinity streak tube, the optimization of electronic optical system of the streak tube, the preparation of vacuum chamber and control system, the system was installed, integrated and tested, and the photocathode detection system was developed. A static test platform for the cathode system was set up and static characteristics were calibrated. The test results show that the excursion ratio of the three slits is 2.8% in the direction of the slit, 6.6% in the direction perpendicular to the slit, and the average magnification is 1.29 with the error in the range of 0.8%, edge spatial resolution better than 10 lp/mm. The newly developed system of X-ray streak camera photocathode detection can be used for the diagnostic study of laser fusion.