A semiconductor light emitting structure including a substrate, a patterned structure, a first semiconductor layer, an active layer and a second semiconductor layer is provided. The patterned structure is protruded from or indented into a surface of the substrate, so that the surface of the substrate becomes a roughed surface. The patterned structure has an asymmetrical geometric shape. The first semiconductor layer is disposed on the roughed surface. The active layer is disposed on the first semiconductor layer. The second semiconductor is disposed on the active layer.