An adaptive evolutionary algorithm（EA） based multiuser detector for direct sequence code division multiple access（DS-CDMA） systems is presented in this paper.The adaptive EA adopts maximum likelihood decision rule to detect the user bit sequences and adaptively adjusts its offspring population size according to the current mutation success probability.The major advantage of the adaptive EA based multiuser detector is that it obtains rather good bit error rate（BER） performance with less generations.Simulation results show the adaptive EA based multiuser detector can always converge to the optimal solution with a smaller number of generations.Compared to ecolutionary programming（EP）

when user nurnber increases from 10 to 20

the corresponding convergence generation decreases from 37.5% to 47.8%.Its BER performance is close to that of the optimal multiuser detector and the computational complexity is polynomial complexity.