Abstract: This paper presents the establishment and validation of the 3D numerical model of plasma ignition to investigate the plasma ignition process in supersonic combustion chamber. Parameters of flow field and chemical reactions in the plasma ignition combustion chamber are calculated. The effects of plasma ignition on combustion are analyzed. The calculation results show that high temperature plasma jet increases the stay time of mixed gas in combustion chamber to improve the ignition efficiency; the combustion zone is incompressible and pressure balanced; velocity vector offset is generated when plasma jet shoots at mixed gases; water is the main product of hydrogen/air combustion and the local temperature is mainly affected by the exothermic reactions.