The invention provides an M*N multicast transmission optical switch, which comprises an optical splitter array used for splitting an input optical signal; an optical switch array used for controlling output of the optical signal; and a substrate, wherein the optical splitter array and the optical switch array are integrated on the substrate, and are made of different waveguide materials; and relative refractive index difference between a waveguide core layer and a waveguide cladding layer of the optical splitter array is smaller than relative refractive index difference between a waveguide core layer and a waveguide cladding layer of the optical switch array, M and N being positive integers. Through integration of the low-refractive-index-difference optical splitter array and the high-refractive-index-difference optical switch array, device loss is reduced, and the obtained M*N multicast transmission optical switch is low in power consumption, fast in response speed and compact in structure.