The present study explored the mechanism of attention bias modification (ABM) on Social Anxiety Disorder (SAD). The participants were assigned into training group (attention modification program, AMP) or attention bias holding group (attention control condition, ACC) randomly. To examine the underlying neural mechanism of ABM training, we used the event-related potentials (ERPs) technology and combined with a Stroop task reflecting the function of cognitive control. The behavioral results showed that after attention training, anxiety symptoms were relieved in both groups. The ERP results showed that, in Stroop task, both AMP and ACC group had an increasing N450 and an increasing SP after training, showing an improvement of cognitive control through this long-term repeated training. We also found the reduced P2 amplitudes after AMP training, but not after ACC training, which suggested that ABM training can reduce the early attention resource allocation of the individual to the relevant stimulus. Therefore, computer-based attention training could generally improve the cognitive control function in anxiety individuals, while manipulative training contingency in ABM mainly modulated the early stage of attention processing. 2019, Springer Nature Singapore Pte Ltd.