The invention discloses an AlGaN / GaN heterojunction HEMT device compatible with the Si-CMOS technology and a manufacturing method thereof. The device comprises an AlGaN / GaN heterojunction epitaxial layer, a passivation layer, a gate dielectric layer, a no-gold gate electrode and a no-gold source and drain electrode. The AlGaN / GaN heterojunction epitaxial layer comprises a substrate, a nitride nucleating layer, a nitride buffer layer, a GaN channel layer, an AlGaN intrinsic barrier layer and an AlGaN heavily doped layer which are arranged from the bottom to the top in turn. The AlGaN heavily doped layer generates charges through the ionized donor to compensate the surface acceptor level of the semiconductor to suppress current collapse and forms ohmic contact with the electrodes through lowtemperature annealing. The no-gold electrodes avoid pollution of Au to the Si-CMOS process line. Current collapse of the HEMT device can be effectively suppressed, the device performance can be enhanced, the process temperature can be reduced and the process flow can be simplified by using double AlGaN layers in the AlGaN / GaN heterojunction through combination of the no-gold electrode process andthe low temperature ohm process so that the technical bottleneck of compatibility of the AlGaN / GaN heterojunction HEMT and the Si-CMOS process can be solved and the manufacturing cost of the AlGaN / GaN heterojunction HEMT can be reduced.