A kind of 2-D hypersonic variable geometry inlet with movable lip along flow direction was designed.Three-dimensional computational fluid dynamics computation was carried out to simulate the flowfield of the inlet.Comparison of the aerodynamics characteristics was made between variable geometry inlet and fixed geometry inlet.Results indicate:by translating lip upstream

the contraction ratio (CR) of the variable geometry inlet decreases from 1.80 to 1.57 and the self-start Mach number decreases from 4.9 to 3.4.Within the Mach number range of 4.0~7.0

no major difference of the isolator exit Mach number and static pressure ratio of both inlets are observed.The mass flow rate and total pressure recovery coefficient of variable geometry inlet are at most 21% and 9% higher respectively compared with fixed geometry inlet.The variable geometry inlet has superior aerodynamic performance.