Abstract: By the development of mobile communication technology, the data transform rate becomes higher and higher, this means that the period of code needs to be smaller and smaller, which will lead to a serious Inter Symbol Interference (ISI). For the requirements of high rate data transform, a Multi Carrier frequency Code Division Multiple Access (MC-CDMA) technology is introduced in this paper, it is the combination of OFDM and CDMA. The structure of transmitting and receiving for MC-CDMA are analyzed, and the signal model for MC-CDMA is built. The multi access interference and the theory of multiuser detection for MC-CDMA are analyzed in detail in this paper. Based on the minimum bit error rate rule, a multiuser detection algorithm is proposed. The ideal minimum bit error rate multiuser detection algorithm is difficult to be performed in practice. We use a method to estimate the probability density function, and then derive an adaptive minimum bit error rate multiuser detection algorithm. The simulation results demonstrate that the proposed algorithm can suppress multi access interference and reduce the bit error rate. Furthermore, this algorithm has the advantage of lower bit error rate than the algorithm based on minimum mean square error rule.