In this paper, we propose dual-polarization technique which double the system capacity without increasing any other bandwidth. In theory, dual-polarization technique can double system capacity by using an orthogonal electromagnetic wave. However, cross-polarization interference and multipath interference degrade system performance in practice. To cope with this problem, we propose Cross Polarization Interference Canceller(XPIC) for ITS/DSRC system which can mitigate the XPI as well as multipath propagation interference. We also analyze and discuss its performance with relevant computer simulation results.