The invention relates to a 
gallium nitride based 
light emitting diode chip and a preparation method thereof, and relates to a 
semiconductor device provided with at least one 
electric potential jumping barrier or a surface potential barrier and specially suitable for 
light emission. The 
gallium nitride based 
light emitting diode chip is structurally characterized in that an epitaxial 
wafer of a conventionally grown LED 
epitaxy structure in the industry of 
gallium nitride based 
light emitting diode chips serves as a substrate, the substrate comprises a 
sapphire substrate, a GaN buffer layer, a 
Si doped n type GaN layer, an InGaN  /  GaN 
multiple quantum well active area and a Mg doped p type GaN layer from bottom to top, then 1-6 
layers of SiO2  /  TiO2 distributed Bragg reflection structure 
layers are alternately deposited, then a composite 
metal Al film forms a reflected current 
barrier layer, and an ITO transparent conducting layer in the industry of the 
gallium nitride based light emitting 
diode chips is assembled at last. According to the 
gallium nitride based light emitting 
diode chip and the preparation method, the 
current crowding effect on a p 
metal electrode in the prior art is eliminated, and the problem of LED chip luminous efficiency reduction due to the fact that the 
metal electrode absorbs photons is resolved.