A semiconductor light emitting structure including a substrate, a second type electrode layer, a reflecting layer, an insulating layer, a first type electrode layer, a first type semiconductor layer, an active layer and a second type semiconductor layer is provided. The second type electrode layer formed on the substrate has a current spreading grating formed by several conductive pillars and conductive walls, which are staggered and connected to each other. The reflecting layer and the insulating layer are formed on the second type electrode layer in sequence, and cover each conductive pillar and each conductive wall. The first type electrode layer, the first type semiconductor layer and the active layer are formed on the insulating layer in sequence. The second type semiconductor layer is formed on the active layer, and covers each conductive pillar and each conductive wall.