Co-Channel Dual Polarization (CCDP) technology is an efficient way to double the link capacity in modern communication system. However, the consequent polarization interferences become an inevitable problem to fight. Therefore, a Cross-Polarization Interference Canceller (XPIC) is necessary against the cross-talks. This paper focuses on the baseband XPIC technology and builds a simulink model to show the XPIC performance in 256-quadrature amplitude modulation (QAM) system. Meanwhile, a two-stage blind adaptive algorithm joint constant modulus algorithm (CMA) and Decision-Directed LMS (DDLMS) is introduced to XPIC to enhance system performance. Simulation results show the feasibility and effectiveness.