Abstract: The turbulent Navier-Stokes equations in combination with two equation k-ε turbulence models were used to simulate the flow field of shear dual-coaxial single element GO2/GH2 injector chamber.The results show that: the shear dual-coaxial injector has two shear combustion surfaces,enabling to achieve a high combustion efficiency at the condition of large mass flowrate,the oxygen injection velocity and the velocity ratio of hydrogen to oxygen are key parameters for shear dual-coaxial injector design,a lower oxygen injection velocity makes the combustion location far away from the faceplate,while a higher velocity ratio makes the combustion location closer to the faceplate.Compared with the gas-liquid shear coaxial injector,a faster oxygen injection velocity and proper velocity ratio of hydrogen to oxygen are preferable choice for design of shear dual-coaxial injector.