Based on space-division-multiple-access scheme, this paper investigates the capacity of Gaussian vector multiple access channels (MAC) for distributed antennas communication system (DWCS). Simulations are conducted to compare the sum rate of Gaussian vector MAC between DWCS and traditional cellular system with co-located antennas. It is shown that the capacity advantages of DWCS-MAC increase with the incremental user number and receiving antennas number, especially when joint decoding is employed. Therefore, DWCS is more applicable to joint processing among multiple antennas and multiple users