Objective To explore the state of cardiac autonomic nerve function in schizophrenia patients with metabolic syndrome and analyze its influence factors and to reduce the occurrence of sudden cardiac death of the patients. Methods A total of 168 cases of patients according with the ICD-10 schizophrenia diagnostic criteria were divided into group A(78 cases of schizophrenia with metabolic syndrome),group B(90 cases of schizophre-nia without metabolic syndrome)and another 92 normal cases were included as control group(group C). Twenty-four hours dynamic electrocardiogram was conducted respectively and the heart rate variability (HRV) was ana-lyzed. Results Values of LF,HF,SDNN,SDANN,RMSSD and PNN50 in group A and group B were much low-er than those in group C and they were statistically significant(P < 0.05). Values of LF,HF,SDNN,SDANN, RMSSD and PNN50 in group B were much higher than those in group A and they were statistically significant(P<0.05). Excluding the influence of schizophrenia ,logistic regression analysis showed that the influence factors of HRV values were course of the disease(OR = 1.864,95%CI 1.110~3.128),age(OR = 1.170,95%CI 1.018~2.491),types of antipsychotic drugs(OR=2.419,95%CI 0.976~1.835),abdominal obesity(OR=2.425,95%CI 1.347~4.366),blood pressure value(OR=1.263,95%CI 1.575~3.937),blood glucose value(OR=3.376, 95%CI 1.359~2.923)and blood lipid value(OR = 2.178,95%CI 1.492~6.756). Conclusions Schizophrenia patients with metabolic syndrome have obvious cardiac autonomic nerve dysfunction. Excluding the influence of schizophrenia itself,the other possible risk factors include course of the disease,age,types of antipsychotic drugs,abdominal obesity,blood pressure value,blood glucose value and blood lipid value.