AbstractInter-cell interference greatly impairs the capacity of CDMA system. 4G era is coming with much severer inter-cell inte-rference, and it's important to find a good solution to inter-cell Interference cancellation. In this paper, the semiblind Hebb-PPIC Multi-User Detection(MUD algorithm which applied in the CDMA uplink is proposed. This approach fully utilizes all known users’ information, performs Hebb-PPIC detector to suppress the int-erferers within the cell, and exploits the blind detector to suppress the inter-cell interference. Simulation results demonstrate that the proposed Hebb-PPIC semi-blind algorithm offers substantial perfo-rmance gains over the blind multi-user detection methods, and the Multiple Access Interference and Near-Far effect can be suppressed effectively in a CDMA uplink environment.