This paper proposes an ultrafast beam smoothing scheme based on the rotation arrangement of phase plates. By rotationally arranging the phase plates with a rotational asymmetric distribution in the laser quad, different spatial phase modulations are first provided for each sub-beam in the laser quad. Then the dynamic interference of the sub-beams with a certain wavelength difference on the target plane makes the speckles within the focal spot sweep rapidly in multiple directions and multiple dimensions, so as to achieve the goal of improving the uniformity of the focal spot in the picosecond time scale. On this basis, the effects of parameters of phase plates, beam arrangement, spatial wavefront distortion, and spatial deviation of laser beams on beam smoothing are analyzed. The results show that in the ultrafast beam smoothing scheme based on the rotation arrangement of phase plates, only the same phase plates with a rotational asymmetric distribution are required to be processed at the same time, which can lower the design and processing difficulty of phase plates. In addition, this scheme is little affected by spatial wavefront distortion, beam arrangement, and spatial deviation of laser beams. Combining the beam smoothing scheme based on the rotation arrangement of phase plates proposed in this paper with the traditional beam smoothing schemes can significantly improve the uniformity of focal spots within a few picoseconds, which can be an effective supplement to the traditional beam smoothing schemes.