Abstract: Various studies have been conducted on the aerodynamic and vortex flow characteristics of 65° swept delta wing or flying-wing configurations with relatively small thickness ratio of the inner wing/body part by both experimental and numerical methods. However, in transonic flow field, wing-body thickness has great influence on the introduce of shock and shock/vortex interactions which can make a significant difference to the vortex breakdown behavior and aerodynamic characteristic of the flying-wing configuration. Based on the experimental data of a low-aspect-ratio common research model with a 65° swept flying-wing configuration and a 0.16 wing-body thickness ratio, through reducing the wing-body thickness while keeping the round leading edge and outer wing geometry identical, wing-body thickness effects on the aerodynamic and vortex flow characteristics of the flying-wing configuration in transonic flow field have been studied numerically methods. The investigation indicated that wing-body thickness ratio reduced model has a gentle change in vertex strength along chord-wise direction and the vortex strength is higher than that of the original model before x/C_r=0.25, meanwhile it can delay vortex breakdown by an angle of 8° compared with the original model at Mach number 0.9.