Abstract: In order to investigation of the jet interaction for finned bodies, the interaction between a lateral jet and the supersonic external flow was investigated numerically by solving the N-S equation. To model more exactly the nozzle geometry and resolve the complex flow associated with the lateral jet problem,the multi-block point matched grid generation technique and "O" type grid technique were applied. The detailed numerical simulation for a variety of missile geometries in the supersonic flow was performed. These include nonfinned axisymmetrical bodies and finned bodies with either strakes or aft-mounted tail fins. The computations were performed at Mach numbers 2 and 4.5. The computational results show significant interactions of the jet induced flowfield with the fin surfaces that produce additional effects compared with the body alone. The computational results were compared with the experimental results from a previously published wind-tunnel study that consisted primarily of global force and moment measurements. The numerical calculations show good agreement with the experimental investigation at supersonic Mach numbers.