The Sidoped nonpolar aplane nAlGaN epitaxial layer with high electron concentration and good surface morphology was successfully grown on semipolar sapphire substrate by metal organic chemical vapor deposition. The effects of indium (In) surfactant and undoped AlGaN buffer layer on the structural and electrical properties of the nAlGaN epitaxial layer were intensively studied. The characterization results show that the anisotropy in crystalline quality of the nonpolar aplane nAlGaN epitaxial layer is effectively suppressed by using In surfactant and undoped AlGaN buffer layer, and its surface morphology and electrical properties are significantly improved. In fact, the electron concentration and electron mobility are determined to be -4.8×1017cm-3 and 3.42cm2/(V·s), respectively.