A purpose of this study is to investigate possibility of pressure drag reduction acting on superstructure. Vortex generator is placed on the top of superstructure model to reduce pressure drag. If by vortex generator ,longitudinal vortex is introduced into behind of model and the back pressure is increase , pressure acting on the model would decreased. The wind tunnel has a measuring section of 0.7m width,0.3m height and length about 2m. In all the experiments Reynolds number based on the representative length scale of the model and free stream velocity will be about 30000. From the measured pressure distribution ,it was shown that the back pressure of superstructure model was increased to 17.4%.