Abstract: Two generic curved surface sidewall compression scramjet inlets with varied sidewall compression angle or with varied sweep angle and sidewall compression angle were studied to improve the performance of the conventional plane compression sidewall compression inlet.The flow field structures and overall performance were studied comparatively at Much number 4 and 6 by means of numerical simulations,and comparisons were made between this concept inlet and conventional inlet.Results indicate the performance of the curved surface inlet is obviously superior to the conventional inlet.The sidewall compression scramjet inlet with varied sweep angle and compression angle has the advantages of both backward and forward sweep sidewall compression inlet,such as: smaller spillage angle at cowl place,weaker cowl shock waves and more stable boundary layer on the top wall.Numerical simulations also show that,at Much number 6 design point,the mass capture ratio of the new curved surface inlet with varied sweep angle increases by 4.1% than that of the conventional inlet,and the total pressure recovery coefficient increases by 5.3%;at Much number 4 starting point,the mass capture ratio increases by 6.3%,and the total pressure recovery coefficient increases by 5.4%.