Abstract: An experimental apparatus was developed for measuring the parameters for the blast waves produced by a high-voltage spark discharge. To investigate the variation and propagation tendency of the blast wave and the scaling law of its parameters, the pressure and arrival time of the blast wave in air were measured at different radii and initial energy using a PCB piezoelectric pressure transducer. The results show that the high-voltage spark-produced blast wave follows the Hopkinson-Sachs scaling law. The comparison between the experimental results and the numerical simulation for a spherical blast wave from a point energy source confirms that the blast wave originated from the high-voltage capacitor spark discharge follows adequately the analytical description and the amount of energy contributed to the direct blast initiation from the spark ignition can be estimated from the first 1/4 cycle current discharge. The composition of the total energy stored in the capacitors, (i.e., 1/2CU2) was further investigated. The results indicate that about 91% of the total energy wastes on the energy loss and ohmic dissipation, and only about 2% contributes to the first 1/4 cycle current discharge energy which is responsible to initiate the detonation. The energy released after the first 1/4 cycle only tends to heat up the surrounding gases.