OBJECTIVE： To observe the efficacy and safety of quetiapine combined with lithium carbonate in the treatment of bipolar disorder manic episode. METHODS： 110 patients with bipolar disorder manic episode were randomly divided into control group （55 cases） and observation group （55 cases）. All patients stopped antipsychotics for 7 d. After the elution period， control group received Lithium carbonate tablet 0.25 g after a meal， twice-3 times a day， for 3 d， then increased to 1-1.5 g， for twice - 3 times， after a meal. Observation group was additionally given Quetiapine fumarate tablet 0.05 g in the first day， 0.1 g in the second day， 0.2 g in the third day， 0.3 g in the fourth day， twice a day， then changed to 0.4-0.6 g， for twice-3 times. The 2 groups were treated for 12 weeks. Clinical efficacy， mania scale （BRMS） score， positive and negative symptoms scale （PANSS） score， cognitive functions score before and after treatment， and the incidence of adverse reactions in 2 groups were observed. RESULTS： The total effective rate in observation group was significantly higher than control group， the incidence of adverse reactions was significantly lower than control group， with statistical significance （P＜0.05）. Before treatment， there were no significant differences in BRMS score， PANSS score and cognitive functions in 2 groups （P＞0.05）. After treatment， BRMS score and PANSS score in 2 groups were significantly lower than before， and observation group was lower than control group， cognitive functions were significantly higher than before， and observation group was higher than control group， with statistical significances （P＜0.05）. CONCLUSIONS： Both efficacy and safety of quetiapine combined with lithium carbonate are superior to lithium carbonate alone in the treatment of bipolar disorder manic episode， and it can significantly improve patients’ cognitive functions.