Both motor and cognitive function rehabilitation benefits can be improved significantly by patients' active participation. To this goal, an attention enhancement system based on the brain-computer interface (BCI) and audiovisual feedback is proposed. First, an interactive position-tracking riding game is designed to increase the training challenge and neural engagement. Subjects were asked to drive one of the avatars to keep up with another by adjusting their riding speed and attention. Second, the subject's electroencephalogram (EEG)-based attention level is divided into three regions (low, moderate, and high) by using the theta-to-beta ratio (TBR). According to the subject's attention states, different speed adjustment strategies are adopted to adjust the tracking challenge and improve the subject's attention. Besides, if the subject's attention focused on the training is moderate or low, an auditory feedback will be given to remind the subject to pay more attention to the training. The contrast experimental results show that subjects' performance indicated by overall attention level and average muscle activation can be improved significantly by using the attention enhancement system, which validates the feasibility of the proposed system for improving the neural and motor engagement.