It is important to understand and control the wake structure behind three dimensional bluff bodies. The purpose of this study is to investigate the effect of velocity disturbances on the wake structure behind a circular disk. The plasma jet generated by a dielectric barrier discharge (DBD) was used as a velocity disturbance. Mean velocity components of streamwise, circumferential and radial direction were measured by X-type hot wire probes. The obtained effects of DBD plasma jet for flow control, the streamwise velocity was increased and the circumferential velocity was decreased.