Abstract: OBJECTIVE To investigate the effect of cytochrome P450 2D6(CYP2D6) genetic polymorphism on blood concentration and clinical efficacy of quetiapine in schizophrenia patients, and to provide evidence for the individualized administration of quetiapine. METHODS A total of 98 patients with schizophrenia were selected and treated with quetiapine alone at a dose ranging from 100 to 750 mg·d^-1 for 4 weeks. The genetic polymorphism of CYP2D6*10 was detected by improved multiple ligase detection reaction. The blood concentration of quetiapine was determined by UPLC-MS/MS. Positive and negative syndrome scale(PANSS) questionnaire were used to estimate the response to quetiapine treatment. Then the differences in blood concentration and clinical efficacy of quetiapine among different genotypes were compared. RESULTS The blood concentration of quetiapine in type of TT was significantly higher than that in types of CC and CT(P<0.05). The blood concentration of quetiapine was correlated with CYP2D6*10 genotype(r=0.558, P<0.001). TT type patients had the highest treatment efficiency, followed by CT type and CC type, and the difference was statistically significant(P<0.05). The reductions of PANSS total score, positive symptom score and negative symptom score in TT type patients were significantly higher than that in type of CC after treatment(P<0.05). CONCLUSION CYP2D6*10 genetic polymorphism can affect the blood concentration and clinical efficacy of quetiapine. Patients with CC type have low blood concentration of quetiapine and poor clinical efficacy, so clinicians shall pay appropriate attention to it.