With increased radio frequency (RF) chains, base station (BS) with multiple antennas consumes more circuit power. Turning off RF chains will help to save energy. However, in turn, it needs more sophisticated user scheduling. Therefore, an energyefficient scheduling scheme is proposed with which users and RF chains are jointly selected at each frame. Here, Lyapunov driftplus- penalty ratio is used to policy design. If the average data arrival rates locate in the capacity region, it is proved that the proposed policy achieves the maximum energy efficiency than any other stationary, randomized, queue-independent policies, while ensuring the stability of the system. At each frame, the selection of users and RF chains depends on the number of selected users, sum queue length of them and energy efficiency they achieve. A key observation is that the numbers of selected users and RF chains should be equal under zero-forcing beamforming. Simulation results have shown that it even achieves higher energy efficiency than the Maximum Weighted Queue scheduling scheme when average arrival rate vector is relative small.