This paper presents an interference suppression using subband adaptive array for space-time block coding (STBC) code division multiple access (CDMA) under the frequency selective fading (FSF) channel. The proposed scheme utilizes CDMA with STBC and receive array antenna with subband adaptive array (SBAA) processing at receiver. The received signal is converted into the frequency domain before despreading and adaptive processing is done at each subband. A novel construction of SBAA is introduced to process CDMA signal based on STBC. Furthermore, to improve the performance of proposed scheme, we also introduce STBCSBAA adopting spreading codes cyclic prefix (CP). Simulation results demonstrate improved performance of the proposed system in the case of single and multiusers environment compare to competing relatives.