A single-element shear-coaxial combustor using gaseous hydrogen(GH2) and oxygen(GO2) was designed and hot-tested.The wall temperature was measured.The combustion flowfield of this GH2 /GO2 single-element combustor was modeled by RANS(Reynolds Averaged Navier-Stokes) and LES(Large Eddy Simulation) methods respectively.The impact of using various turbulence and turbulent combustion models was investigated to obtain the model combination which best represented the experimental data in the RANS modeling.The flamelet model was used in the LES modeling and the validity of its application to the GH2 /GO2 combustion in the combustor was carefully examined.The combustor wall heat flux distributions of both RANS and LES results show good agreement with the experimental data.The experimental wall temperature distribution can be clearly explained through analyzing the inner flowfield structure.The results indicate that both RANS and LES used in this paper can give good predictions of the development of the whole flowfield and the combustion completion length.LES can resolve large-scale flow motions in the combustor and accurately predict the influence of the wall heat loss on the combustion efficiency. A single-element shear-coaxial combustor using gaseous hydrogen (GH2) and oxygen (GO2) was designed and hot-tested. The wall temperature was measured. The combustion flowfield of this GH2 / GO2 single-element combustor was modeled by RANS Averaged Navier-Stokes) and LES (Large Eddy Simulation) methods respectively. The impact of using various turbulence and turbulent combustion models was investigated to obtain the model combination which best represented the experimental data in the RANS modeling. Flamelet model was used in the LES modeling and the validity of its application to the GH2 / GO2 combustion in the combustor was carefully examined. The combustor wall heat flux distributions of both RANS and LES results show good agreement with the experimental data. through analyzing the inner flowfield structure.The results indicate both both RANS and LES used in this paper can give good predictions of the developme nt of the whole flowfield and the combustion completion length .LES can resolve large-scale flow motions in the combustor and precisely predict the influence of the wall heat loss on the combustion efficiency.