There is provided a method for performing an intra-packet data service node (PDSN) soft handoff. The method is implemented by setting up a channel passing through a target base station controller (T-BSC), a source base station controller (S-BSC) and a PDSN by establishing a direct channel link between the S-BSC and the T-BSC in an active packet session mode, performing a handoff between the S-BSC, the T-BSC and a mobile station (MS), transmitting or receiving user packet data exchanged between the MS, and the S-BSC and the T-BSC to or from the PDSN through the established channel link and sending or receiving user packet data exchanged between the MS and the T-BSC to or from the PDSN through the established channel link when the handoff is completed.