In this paper we analyze the performance of 2*4 MIMO-MC-CDMA system in MATLAB which highly reduces BER. In this paper we combine MIMO and MC-CDMA system to reduce bit error rate in which MC-CDMA is multi user and multiple access schemes which is used to increase the data rate of the system. MC-CDMA system is a single wideband frequency selective carrier which converts frequency selective to parallel narrowband flat fading multiple sub-carriers to enhance the performance of system. Now MC-CDMA system further improved by grouping with 2*4 MIMO system which uses ZF (Zero Forcing) decoder at the receiver to decrease BER with half rate convolutionally encoded Alamouti STBC block code is used as transmit diversity of MIMO through multiple transmit antenna. Importance of using MIMO-MC-CDMA using convolution code is firstly to reduce the complexity of system secondary to reduce BER and lastly to increase gain. In this paper we examine system performance in diverse modulation techniques like, 8-PSK, 16-QAM, QPSK, 32-QAM, 8-QAM and 64-QAM in Rayleigh fading channel using MATLAB.