To solve the problems of dynamic focusing, correction of magnification, and vibration with noise in volumetric 3D display technique by reciprocating scanning, a method of volumetric 3D display by scanning with multi-screen in parallel motion is proposed. In this method, multi-screen and multi-mirror in circle-curvilinear motion are adopted to maintain the optical path constant between fixed projector and moving screen, so as to form a size-invariable and sharp focused 2D image sequence, avoiding the problem of dynamic focusing and correction of magnification. With the persistence of vision, the 2D image sequence is perceived as a 3D image with physical depth in which uniform voxels are allowed to be arranged uniformly without physical dead zone. By arranging all the moving components symmetrically in corresponding circles and driving them in even velocity, the inertia forces are balanced automatically so as to solve the problem of vibration with noise. A prototype is manufactured and the method is verified by experiments.