The invention discloses an optical path rapid-switching device which comprises a lens fixing part, a cam part, an elastic piece, a mounting seat and a motor, wherein the lens fixing part and the cam part are all detachably mounted on the mounting seat; the cam part comprises a cam; a reflective lens is fixed at one end of the lens fixing part, and the other end of the lens fixing part is connected with one end of the elastic piece; a rolling wheel is arranged in the middle of the mounting seat; the rolling wheel is in contact with the circular arc section of the side wall of the cam under the tensioning force action of the elastic piece; when the cam rotates, the lens fixing part drives the reflective lens to rotate back and forth between two different positions, so that the reflection direction of the optical path incident on the reflective lens is changed. The optical path rapid-switching device is stable in operation, can flexibly regulate the angle of incidence of the incident light, can fully replace an oscillating mirror, and can further reduce the cost.