A multi-layer thin films structure based on the microcavity effect of metal thin film-distributed Bragg reflector (DBR) to enhance light absorption of monolayer tungsten disulfide (WS2) was proposed. Its optical transport characteristics was studied by optical transfer matrix theory. It is found that the microcavity effect of the metal thin film-DBR forms the maximum value of the electric field strength between the cover layer and spacer layer, which effectively promotes the interaction between incident light and the monolayer WS2. As the thickness of the metal layer, spacer layer and cover layer are comprehensively optimized, the light absorption of monolayer WS2 at 612 nm increases by 38 times, up to 78.42%. Furthermore, the influenced of light incident angle, period of the DBR and the refractive index of space layer on the light absorption of monolayer WS2 were discussed. The research results show that changing of the above structural parameters can effectively regulate the absorption peak value of monolayer WS2. The research results provide new ideas for the preparation of high-performance monolayer WS2 photodetectors and other new optoelectronic devices.