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Objective To investigate the effect of reducing antipsychotic dose on clinical symptoms in patients with stable schizophrenia. Methods Seventy-five patients with stable schizophrenia taking olanzapine or risperidone were enrolled. Patients were randomly divided into dose reduction group (37 cases) and maintenance group (38 cases). The dose of the risperidone or olanzapine was gradually reduced by 50％ in the dose reduction group within six months whereas remained unchanged in the maintenance group. The Positive and Negative Symptom Scale (PANSS), Calgary Depression Scale (CDRS), Personal and Social Performance Scale (PSP), Insight and Treatment Attitude Questionnaire (ITAQ) and Extrapyramidal Side Effects Scale (RSESE) were assessed at baseline, 3 months, 6 months and 12 months. Results There were one and two cases dropped out due to the relapse in dose reduction group and in maintenance group, respectively. The recurrence rates were 2.7％ in dose reduction group and 5.3％ in maintenance group (P<0.05). The interaction effects of PANSS positive symptoms, negative symptoms and general pathological symptoms, ITAQ,RSESE, PSP were significant (P<0.05). The main effect of PANSS negative symptoms and PSP group was significant (P<0.05). Compared with the maintenance group, PANSS negative symptoms of the dose reduction group were significantly lower at 6 and 12 months (P<0.05). PSP scores were significantly higher in the dose reduction group than in maintenance group (P<0.05) at 3, 6 and 12 months. Conclusion Reducing the dose of risperidone or olanzapine slowly in patients with stable schizophrenia within six months reduces negative symptoms and adverse reaction, improves social function without increasing positive symptoms.