In order to make aero-engine exhaust system meet the needs of high radar stealth performance and thrust vectoring performance, taking the spherical convergent vector nozzle as the research object, the influence of the geometric parameters of the inner-flow shielding strut modification on the backward radar cross-section (RCS) of the nozzle is analyzed, and the iterative physical optics method is used to calculate the backward RCS of the spherical convergent vector nozzle under different strut inclination angles, bevel angles, and the number of struts. The calculation results show that within both the two detection planes, the inner-flow shielding struts can effectively reduce the backward RCS of the nozzle. With regard to the strut inclination angle, when the strut inclination is at an angle of 50° to the pitch detection plane, the RCS reduction is best in effect, i.e. reaching 71%. When the strut inclination is at an angle of 30° to the yaw detection plane, the best RCS reduction reaches 21%. With regard to the strut bevel angle, when the strut bevel is at an angle of 45° to the pitch detection plane, the RCS reduction is best in effect, i.e. reaching 64%. When the strut bevel is at an angle of 40° to the yaw detection plane, the best RCS reduction reaches 19%. When the number of struts is 16 in all, the best RCS reduction effect can be obtained within both the detection planes.