Abstract: In present paper,the unsteady flow field of a blast wave interaction with a sphere traveling in supersonic speed is determined using a shock-capturing,finite difference approach and hybrid scheme.The presented numerical results compare favorably with the available experimental data,and the weak contact surface of bow shock interaction with the reflected blast wave obtained is shown to agree better with that of experiment.The flow of a blast wave encountered a sphere traveling supersonically at -5° angel of attack is studied further.