In this paper, a 2times2 MIMO-OFDM digital baseband receiver for IEEE 802.16 WMAN-OFDM PHY is presented. The inner receiver design includes the timing and carrier frequency synchronization, the channel estimation and the MIMO detection with adaptive equalization technique. In order to enhance the robustness of the system, the BLMS algorithm is derived to track the channel variation for the Alamouti-scheme STBC FEQ. The simulation results demonstrate that the MIMO receiver with adaptive equalization technique has superior SER performance over frequency selective fading channel.