A solid state light emitting semiconductor structure and an epitaxy growth method thereof are provided. The method includes the following steps: A substrate is provided. A plurality of protrusions separated from each other are formed on the substrate. A buffer layer is formed on the protrusions, and fills or partially fills the gaps between the protrusions. A semiconductor epitaxy stacking layer is formed on the buffer layer, wherein the semiconductor epitaxy stacking layer is constituted by a first type semiconductor layer, an active layer and a second type semiconductor layer in sequence.