The invention provides an epitaxial method of low-temperature P-type GaN with In and Al doping and gradient growth of In and belongs to the technical field of photo-electronics. The method herein grows a low-temperature gallium nitride layer with doped Al and In and gradiently-doped in; doping of In helps increase Mg doping concentration and decrease Mg activity energy, thereby increasing implantation of effective holes; In has large atoms, sudden doping of In causes great lattice mismatch, and gradient doping of In allows the lattice mismatch of the low-temperature gallium nitride layer and alast barrier layer to be buffered, thereby protecting crystallization quality of a whole LED; doping of Al helps slightly raise the conduction band energy level, thereby effectively blocking electrons from migrating from a multi-quantum-well light-emitting layer to a low-temperature p-type GaN layer, and reducing nonradiative recombination between the electrons, entering the low-temperature p-type GaN layer from the multi-quantum-well light-emitting layer, and holes in the low-temperature p-type GaN layer.