Self-report measures of state anxiety(STAI_S), trait anxiety(STAI_T), depression, attentional control, attention to positive information(API), and attention to negative information(ANI) were conducted among 481 Chinese undergraduate students to investigate the impacts of anxiety and depression on attentional bias and the mediating role of attention control. It was found that API was positively correlated with attention control, and negatively correlated with state anxiety, trait anxiety, and depression. ANI was negatively correlated with attention control, and positively related to state anxiety, trait anxiety, and depression. API was significantly predicted by trait anxiety, attention focusing, and attention shifting, while ANI was significantly predicted by state anxiety,depression, and attention focusing. Furthermore, attention shifting and attention focusing mediated the relationships between state anxiety, trait anxiety, depression with API and ANI. The results demonstrated that attentional control may serve as a protective factor for alleviating or eliminating the negative impacts of anxiety and depression on attentional biases.