The invention relates to an in situ test platform for testing ultraviolet intensity distribution in an ultraviolet sterilizer. The ultraviolet sterilizer comprises a cavity, a sleeve and an ultraviolet light tube. The in situ test platform provided by the invention is characterized by comprising a platform frame body, wherein the platform frame body is provided with a movable guide rail which canmove in horizontal and vertical directions, the moving end of the movable guide rail is fixed with an ultraviolet intensity test probe; and the cavity of the ultraviolet sterilizer is fixedly connected onto the platform frame body, and the top of the cavity is provided with a test hole. The ultraviolet sterilizer is provided with a reference probe used for detecting variation of the ultraviolet intensity output by the ultraviolet light tube; and the test probe and the reference probe are all electrically connected with a recording and displaying device. The invention has the advantages that accuracy of the test result is high, the in situ test platform can be applied to tests of intensity distribution of various tubular ultraviolet sterilizers, and further the sterilization efficiency of the sterilizer can be evaluated.