We have developed a thermochemical nonequilibrium code for simulating a laser-induced blast wave with partially ionized air and wave drag reduction resulting from its interaction with a bow shock in front of a blunt body. We performed numerical simulations of blast wave generation using laser ray-tracing method by changing an effective diameter of collecting lens and subsequent interacting flowfield by changing an aspect ratio of a blunt body and Mach number. A tear-drop-shaped blast wave is generated by laser focused from a blunt body head, and low-density region formed in the blast wave becomes slender as an effective diameter becomes larger. The wave drag is reduced while a vortex region generated by the interaction is moving along the wall surface for all the effective diameters and all the aspect ratios. There is an optimal value of the effective diameter for the wave drag reduction. The lower aspect ratio a blunt body has, the longer time the vortex region stalls for and the more effectively the wave drag is reduced. On the other side of the wave drag reduction, the momentary heat flux at the stagnation point is increased in more than one order. Time-averaged drag is monotonically decreased with pulse repetition frequency.