A light guide element, a light source module, and a display are provided. The display includes a display panel and the light source module. The light source module includes a light source and the light guide element, wherein light emitted by the light source is guided toward the display panel by the light guide element. The light guide element includes a plurality sidewalls and a bottom wall. The sidewalls surround the bottom wall and are connected with each other to form a light entering opening, a light exiting opening, and an inner reflection room. Each of the sidewalls and the bottom wall has at least one reflection surface, wherein the reflection surface faces the inner reflection room.