The present invention provides a space rotating target video Inverse Synthetic Aperture Radar (Inverse Synthetic Aperture Radar, ISAR) imaging method based on a transmission pulse cycle delay design.A technical characteristic of the method is: designing a transmission pulse sequence by using a feature of target rotation, so that the sampling quantity required in an ISAR imaging corner is sufficient, to implement ISAR imaging of a rotating target. The method comprises the following steps: estimating a rotating target frequency; designing a transmission pulse string according to the estimated rotation frequency; transmitting the designed transmission pulse, extracting a pulse echo corresponding to a corner time required by imaging in an echo; performing precise estimation on the target frequency by using dichotomy loop iteration, and obtaining an ISAR image of a target; and generating ISAR images of different moments of the target, to obtain a video ISAR image. According to the method proposed in the present invention, a defect that a rotating target ISAR image cannot be obtained by using a conventional ISAR imaging algorithm is overcome, so that not only video ISAR imaging on the rotating target is implemented, but also estimation precision of the target rotation frequency is improved.