Objective To investigate the abnormality of cerebral laterality of the three attentional networks (alerting, orienting, executive control) in patients with bipolar depression disorder. Methods Patients with bipolar depression disorder (n=28) and healthy controls (n=40) were selected. Lateralized Attention Network Test (LANT) was used to explore the efficiency of the networks in bilateral cerebral hemisphere. Results In the response time (RT), there was a significant interaction between groups and hemispheres in orienting network (F=4.67, P=0.03). The result of post hoc test indicated that the RT in the orienting function was significantly longer in the left hemisphere than in the right in control group (t=-4.47, P＜0.05). There was no significant difference in the orienting network between the left and right hemisphere in patients with the depressive bipolar disorder. Conclusion Attention is impaired in patients with depressive bipolar disorder in which the disappearance of left hemisphere advantage of orienting network is the main manifestation of attention impairments.