The aim of present study is to design the Jet pump using CFD techniques to arrive at a solution which can meet the mass flow pumping requirements as demanded by the combat aircraft. Initial design for Jet pump is based on ESDU methods for a given mass flow inputs, followed by 3D steady state numerical simulations with various turbulence modeling using ANSYS Fluent R15.0. Initially, CFD methodology has been validated against the experimental results available in the open literature for the water jet pump geometry. CFD results show good match with experimental data up to the maximum efficiency point followed by large deviations. After validation, the final design obtained from empirical relations had been analyzed using similar CFD approach followed by fine tuning and resizing the jet pump parts such as mixing chamber, diffuser, secondary inlet bell mouth and reservoir shaping towards finalizing the design of Jet pump for practical applications.