The invention relates to a device and method for acquiring a computed hologram of a three-dimensional motion object. The device comprises a video camera and a computer that are connected, wherein an annular micro lens array is arranged between a shot three-dimensional motion object and the video camera. According to the method, the computed hologram of the three-dimensional motion object can be obtained by the steps of simultaneously acquiring a plurality of projections by using a technology for synthesizing a micro lens array with an intermediate viewpoint projection; acquiring frequency spectrum information of the three-dimensional object according to a three-dimensional Fourier rotating paraboloid; extracting the frequency spectrum information of the three-dimensional object from the acquired projection frequency spectrum and filling a two-dimensional matrix; and coding the matrix. The method is used for synthesizing the computed hologram of the three-dimensional motion object with simple acquisition information and high calculation efficiency and comprises the main processes of: acquiring 18 projections and transmitting projection information to a computer by the micro lens array and the video camera; extracting the projection information at the specified position and numbering according to the sequence by the computer; acquiring a synthesized image between adjacent projections by adopting an intermediate viewpoint projection synthesizing technology and further obtaining more two-dimensional projections of the three-dimensional object; and carrying out the Fourier transform on all projections, extracting information of a round frequency spectrum from a physical area of each projection frequency spectrum and filling the two-dimensional matrix according to the specific sequence, acquiring the two-dimensional matrix containing three-dimensional scene depth information and coding the matrix to obtain the computed hologram of the three-dimensional motion object.