A parametric description method was established using NURBS(non-uniform rational B-spline) curve

and effects of two key parameters on the inlet performance were studied by numerical simulation.Results show: (1) Controlled vortex induced by backswept convex pon the second S-duct can lead low momentum flow to side regions of AIP(aerodynamic interface plane)

and the separation region can be reduced.The value of convex angle need to be selected appropriately

otherwise the convex angle is not conducive to the improvement of the vortex-controlled serpentine inlet performance. (2) Uplifting the lower wall of second S-duct properly could alleviate the adverse pressure gradient on the wall

which has positive effects on the flow within ducts. (3) While the design parameters are chosen appropriately

the total-pressure recovery coefficient of the vortex-controlled serpentine inlet is 0.9667 under design conditions

the distortion index is 0.2451

and the inlet performance has been significantly improved.