The invention discloses a mixed silicon single mode annular cavity laser based on microstructural silicon waveguide frequency selection, comprising a silicon substrate, a silicon dioxide layer formed on the silicon substrate, a silicon annular waveguide layer formed on the silicon dioxide layer, a bonding buffer layer formed on the silicon waveguide layer, an N type contact layer formed on the bonding buffer layer, an N type electrode formed in the middle on the N type contact layer, an annular quantum well active region formed in an annular part of the N type electrode on the N type contact layer, a P type annular contact layer formed on the annular quantum well active region, a P type annular cover layer formed on the P type annular contact layer and a P type electrode formed on the P type annular cover layer. The structure is in high density integration, single longitudinal mode working and high-efficiency coupling outputting; and more importantly, according to the mixed silicon single mode annular cavity laser disclosed by the invention, technological steps of conventional DFB distributed feedback grating manufacturing, III-V group material secondary epitaxy and the like are saved in technological processing, and the complexity is lowered.