In this paper the principle of image rotating mechanism based on prism is introduced and the image rotating mechanism using Pechan prism matching the high speed rotating mirror camera is designed. The designed mechanism can be used in FJZ-250 or SJZ-15 type rotating mirror camera as a fixed part. Equipped with the designed mechanism, the rotating mirror cameras can rotate the image of the object by any angle in the range of 0°~360° before recording it. As a result, the measurement problem of different research directions of detonation test is solved when multiple cameras are used synchronously, which plays an important role in acquisition of experimental data and debugging of outdoors targets, thus, it is a great convenience for the camera. The results of the image quality specification experiment indicate that the equipment of the designed image rotating mechanism based on Pechan prism induced no degradation to the image quality and even slightly improved it.