Based on the advantage of RBF neural network control method, a new discretetime adaptive sliding mode control method, which is one of the active control algorithms, was applied for seismically excited building structures. The undue chattering effect and the major disadvantage of conventional sliding mode controller have been removed by introducing RBF neural network controller to suppress parameter vibrations and perturbations greatly. This paper proposed several ways to get the switch surface and to design the feedback controller. For numerical application,a threestory shear building model subjected to ground excitations was considered. The ground accelerations recorded in two different earthquake events were used to evaluate the effectiveness of the control algorithm for varied disturbances. The simulation results show preliminarily that our new discretetime adaptive sliding mode control method is quite effective: not only can it reduce the peakresponse of the ground motion, but also it can keep the chattering effect sufficiently low so as to ensure the system stable.