A light harvesting lens module for collecting an ambient light includes a plurality of annular lenses. The annular lenses are arranged in order from center to outside to form a disc-structure. Each annular lens has a light-input curved surface and a light-output curved surface. The light-input curved surface is in opposition to the center. The light-output curved surface is in opposition to the light-input curved surface, and faces the center. The light is incident on the light-input curved surface, and is refracted and tend to concentrate by the light-input curved surface. Then, the light is emitted from the annular lens, and is refracted to the direction of the center by the light-output curved surface. The ambient light is able to be compressed into a point light by the lens module, so as to increase the concentration ratio and the compression ratio to further get the effective advantage.