The invention relates to a circularly polarized light beam splitter and a manufacturing method thereof. The circularly polarized light beam splitter comprises a substrate and spiral wire gatings. A plurality of groups of spiral wire gatings are arranged on the substrate vertically and are distributed in an array. Each spiral wire gatings group includes eight single spiral wire gatings; and the eight single spiral wire gatings having identical rotation directions are arranged on the same straight line and the initial rotation angles of the eight single spiral wire gatings are increased successively by 22.5 degrees. The initial rotation angel of the first single spiral wire gating in each spiral wire gatings group is 0 degree. When circularly polarized light enters vertically from one side of the spiral wire gating array and two beams of light is transmitted from the other side of the beam splitter, one beam of transmitting light is transmitted according to an original direction and a light splitting angle is formed between the other beam of light and one beam of light. On the basis of the structure, the wavelength of circularly polarized light that is allowed to be transmitted by the circularly polarized light beam splitter can reach 0.6 to 0.86 microns, the transmittance of the circularly polarized light can reach 86%, the splitting ratio can reach 1:0.0029, and the splitting angle can reach 24.7 degrees.