In the present study, we developed a mental switch-based asynchronous brain-computer interface for 2D cursor control. Two mental switches were designed: one was to switch from non-intentional to intentional control state, and the other one for conducting the reverse process. 2D control and mental switches are all based on three-class motor imagery. With four subjects participating in the study, the experimental results demonstrated the efficiency of the proposed asynchronous 2D control strategy.