The invention discloses a transverse electric-pass polarizer based on composite waveguides. The polarizer comprises an incident silicon waveguide, an emitted silicon waveguide, and a middle coupling portion between the incident silicon waveguide and the emitted silicon waveguide. The middle coupling portion is of a five-layer waveguide structure arranged on an SOI substrate, the five-layer waveguide structure sequentially including, from bottom to top, a lower silicon layer, a lower silicon dioxide layer, an upper silicon layer, an upper silicon dioxide layer and a metal chromium layer. When a TM mold transmitted from the incident silicon waveguide passes by the middle coupling portion, the TM mold is coupled from the lower silicon dioxide layer to the upper silicon dioxide layer and is absorbed for attenuation by the metal chromium layer. When a TE mold transmitted from the incident silicon waveguide passes by the middle coupling portion, the TE mold is transmitted along the lower silicon dioxide layer and will not be coupled to the upper silicon dioxide layer. The polarizer has the advantages of small size, high extinction ratio and low insert loss, enables coupling loss to be reduced, and facilitates optical integration.