The invention relates to a coarse and fine scanning rotating prism device, which comprises a prism and an inner and outer prism frame assembly, a worm and gear movement mechanism, a rotary motor, a yaw motor and a rotating half shaft assembly, an anti-backlash motor and an anti-backlash gear assembly, a rotary encoder assembly, a deflection encoder assembly, a rectangular frame and a base, wherein the rotary motor drives the prism and the inner and outer prism frame assembly through the worm and gear mechanism to realize full circumferential rotation, and the yaw motor is directly coupled with the rectangular frame to realize the yaw movement of the prism and the inner and outer prism frame assembly; and the whole device is arranged on the base. The prism is driven by the worm and gear mechanism to realize the full circumferential large-range rotation, and the coarse scanning requirements of dynamic beams are met; and a rotary movement mechanism and a yaw movement mechanism are nested to be combined, so that the integration of coarse and fine scanning functions is skillfully realized in a single set of devices, and the problems that the dispersal spatial structure is brought by a coarse and fine scanning separation design and the coarse and fine error term of the system is difficult to separate and traceably amend are avoided.