The invention discloses a method for improving the combustion efficiency through optical focusing and an incinerator. The method and the incinerator are mainly used for solving the technical problem that an existing combustor is insufficient in combustion or cannot save enough energy and the like. According to the technical scheme, the method is characterized in that light rays generated during combustion of a combustor in an incinerator body (1) are reflected to reflector sets (4) through concave lens sets (2) and then are refracted upwards, convex lens sets (3) sequentially conduct focusing, finally, the light rays are gathered at the position of the lower portion of an upper exhaust port (11) of the incinerator body (1) to be focused again, and therefore a high-temperature focusing combustion point is formed; and garbage and other comburent combusted in the incinerator body (1) can generate the light rays in the combustion process and can also generate smoke reaching a certain temperature due to insufficient combustion, the smoke which is about to be exhausted can be sufficiently combusted again, the temperature of the smoke which is about to be exhausted is increased again, and therefore the content of dioxin in the smoke is effectively reduced. The method and the incinerator are mainly applied to the combustion field.