Objective To investigate the effects of olanzapine on serum vascular endothelial growth factor（ sVEGF） levels in first-episode schizophrenic patients and its relationship with clinical efficacy. Methods A total of 40 first-episode schizophrenic patients（ patients group） were enrolled in the study. They were treated with olanzapine only for 4 weeks. The psychiatric symptoms were estimated using the Positive and Negative Syndrome Scale（ PANSS）. sVEGF levels were determined in patients and 40 normal controls（ normal group） using enzyme linked immunosorbent assay（ ELISA）. Results Before treatment， the sVEGF levels in the patient group was（ 331.8±80.1） pg/ml， which were significantly lower than that in the normal group （506.1±211.5） pg/ml. The sVEGF level after taking drug was（ 475.7±128.5） pg/ml， which was higher than before， and the difference was statistically significant（ t=6.489，P ＜ 0.05）. However there was no significant difference when compared with the control group（ P＞ 0.05）. The PANSS score of the patients was lower than that of the patients before treatment， and PANSS reductive ratio was positively correlated with sVEGF changes （r=0.439， P=0.005）. Conclusions It is suggested that sVEGF may be an suitable biomarker for schizophrenia. Effective antipsychotic drugs can increase the sVEGF level and the change of sVEGF may be a correlation index of the antipsychotic drugs efficiency.