The utility model discloses an LED low-position lamp for roads and bridges. The LED low-position lamp comprises a polarizing lens, an LED light source, a support, a lamp shell and a light outlet plate. A light outlet of the lamp shell is of an inclined downward light outlet structure with the upper end extending forwards and the lower end retracting backwards. The light-emitting surface of the lens body is designed into the sawtooth-shaped light-gathering surface, the transition curved surface and the sawtooth-shaped light-expanding surface which are matched with the plane light-entering surface and the curved surface light-entering surface corresponding to the light-entering surface, light can be gathered on one side of the light-emitting range of the lens body through the sawtooth-shapedlight-gathering surface, a large polarization angle is created, far-side strong light projection is achieved; the transition curved surface adopts a high-order free aspheric surface to be connected between the sawtooth-shaped light gathering surface and the sawtooth-shaped light expanding surface for smooth transition, and is used for uniform light projection of the middle part, so that the problem of a dark area is avoided; and the sawtooth-shaped light expanding surface of the light expanding part diffuses light to the other side of the light emitting range of the body and is used for near-side weak light projection, so that the light projected to the wall surface is uniform.