The invention proposes an LED epitaxial wafer and a forming method thereof. The forming method comprises a first step of providing a substrate and forming a buffer layer on the substrate; a second step of forming a semiconductor material layer of a first doping type on the buffer layer; a third step of forming a quantum well structure on the semiconductor material layer of the first doping type; a fourth step of forming an electron blocking layer on the quantum well structure; and a fifth step of forming a semiconductor material layer of a second doping type on the electron blocking layer. The fourth step comprises forming a first AlxGa1-xN layer on the quantum well structure, and forming a second AlxGa1-xN layer on the first AlxGa1-xN layer. In the formation of the first AlxGa1-xN layer, a component x of an Al is gradually changed from a first component value to a component value, and the second component value is larger than the first component value. In the formation of the second AlxGa1-xN layer, a component x of an Al is constant. The LED epitaxial wafer and the forming method thereof can improve the internal quantum efficiency of LED chips, promote the light-emitting efficiency of the epitaxial wafer, and are suitable for the needs of high-power epitaxial wafers.