In this paper, we propose a multitone code-division multiple-access (MT-CDMA) system employing antenna array at base station with quaternary phase shift keying modulation (QPSK) modulation. Based on the detailed analysis of interference characteristics the BER performance of the proposed MT-CDMA system is provided. With regard to spatial domain combining, the optimum and suboptimum combining weight is derived while the suboptimum set of weights is simplified on sense of that only the knowledge of array vector of desired user alone is sufficient for the optimum combining. Simulation results verify the analysis and show that better performance is achieved for the proposed antenna array system than single antenna MT-CDMA approach.