Effect of injection angle in mixing and combustion in a scramjet combustor is numerically simulated. Three dimensional Navier Stokes equations alongwith k-ε turbulence model are solved using commercial CFD software. Both infinitely fast rate kinetics and single step finite rate kinetics are used to model chemical kinetics. Turbulence chemistry interaction is modeled by Eddy Dissipation Concept (EDC). Good agreement between the computed and experimental results for angular injection (30°) and perpendicular injection forms the basis of further analysis. More flow blockage has caused significant upstream interaction for perpendicular injection and terminal shock is seen to anchor upstream of combustor step; while for angular injection, the flow field is predominantly supersonic. Single step finite rate chemistry show comparatively low pressure and lesser upstream interaction because of the presence of backward reaction. Thermochemical variables are analysed to study the effect of angle of injection on nature of combustion (whether premixed or diffusive), heat release pattern, combustion efficiency etc.