We present the results of the numerical analysis for the wave drag reduction by a single pulse energy deposition in the supersonic flowfield around a sphere. The wave drag for the sphere is reduced as a result of the interaction between the blast wave produced by the energy deposition and the bow shock developed in front of the sphere. We have investigated the interaction mechanism and the drag reduction effect by the pulse energy deposition. The optimal energy deposition conditions to obtain the maximum drag reduction effect are found by the parametric studies varying the amount and the location of energy deposition. It is also found that the drag reduction effect is proportional to the freestream Mach number under the constant energy deposition condition.