Abstract: The inlet model of HyShot program was simulated.The flow fields of the HyShot inlet under the design and non-undersign conditions,as well as the inlet's performance with the variation of Mach numbers were obtained.The design for slotting at two-dimensional hypersonic inlet was brought forward hereby and a two-dimensional hypersonic inlet working at Mach number 4.0～6.0 was designed.Furthermore,two new inlet models were designed by raising or lowering the height of the original slot.By comparing the simulation results of these three inlet models and the inlet without slot under different Mach numbers,it shows that the spillage slot improves the performance of inlet effectively and expands the inlet's operating region.It can also be found that different slot heights would fairly affect the performance of inlet.