Abstract: Abstract: In this paper, the iteration of joint equalization and decoding is studied. And it presents a low complexity equalization algorithm based on iteration. The algorithm approximates the exponential operation to the Accumulation operation, and then computes the soft information of the iteration equalization through the minimum mean square error estimated symbol or the priori information feedback from the decoding respectively in the different situations. So it avoids the exhaustive search among the constellation, and reduces the complexity accordingly. The simulation and the analyses show that it reduces the complexity effectively at the cost of negligible deterioration on the performance suffering the ISI channel. And it is effectively especially for the high order modulation. The computing times of ρ_n,i which is more complicated in equalization in my algorithm is only one fourth of the original algorithm.