In this paper the design of an inlet for a combined turbojet and ramjet engine operating in thehypersonic regime presents a number of challenges, due to the complex flow phenomena that occur atthese high speeds. behavior and performance of the inlet under a range of different velocity conditionsis carried out by using CFD, it is possible to analyze the flow separation and shock formation that may occur in the inlet at hypersonic velocities, and to evaluate the effectiveness of different design features(such as shock cones or bleed ports) in mitigating these effects. One approach to performing CFD on acombined turbojet and ramjet engine inlet in the hypersonic regime is to iterate through a range of different velocities and analyze the flow behavior at each velocity. This can help to identify any issues or performance limitations that may occur at different velocities, and suggest ways to improve the inlet design. Overall, the use of CFD for inlet analysis can be an important part of the design process for combined turbojet and ramjet engines operating in the hypersonic regime, helping to ensure that the inlet performs effectively and efficiently under these demanding conditions. Also CFD is carried out for the combine engine and also thrust with different chamber pressure is plotted and combined effect of turbo ramjet engine is evaluated.