The usage of productive baseband receivers are portrayed by reasonable computational load is an urgent point in the advancement of transmission frameworks misusing assorted qualities in various spaces.Several research works have been published in the literature ofspace-time block codes multi-carrier code-division multiple-access (STBC MC-CDMA)Systems based on minimum conditional bit error rate Criterion. As like, in our previous paper, an efficient STBC communication system was performed using oppositional krill herd algorithm (OKHA). To overcome the drawbacks in the previous work, in this work we proposed a hybrid Particle swarm optimization (PSO) and group search optimization (GSO), called PSGSO based Multi-User Detection in STBC MC-CDMA Systems. In this paper, we use the Alamouti's STBC encoder for transmitting sequence and the channel estimation matrix is optimally evaluated using PSGSO algorithm. The simulation results show that the proposed algorithm is properly reducing the bit error rate (BER), symbol error rate (SER) and properly increase the spectral efficiency value compare to other techniques.