The paper presents a new iterative receiver algorithm which is proposed for the high order modulation system. It has low complexity and good performance. Firstly, the algorithm uses zero forcing multiuser detection (MUD) algorithm. Then it is performed by a soft-input soft-output (SISO) multiuser detector and a bank of SISO channel decoders, through an iterative process. And the SISO multiuser detector adopts a novel soft interface cancellation method based on a linear minimum mean-squared error (LMMSE) filter. This makes the detector overcome the limitation of binary phase shift keying (BPSK) while the complexity is polynomial in terms of codes to be detected in the system. Simulation results show that, the performance of the proposed iterative receiver can approach that of single code maximal likelihood detection (MLD) only after two iterations.