Abstract: Objective To analyze the relationship between psychotic symptoms and body mass index (BMI) and brain mass index in patients with first-episode schizophrenia. Methods We identified 97 patients with first-episode and drug-free schizophrenia and compared their BMI and scare MRI results with 97 healthy participants. Results There were no statistically significant differences in BMI, volume of white matter and volume of grey matter between the patients with schizophrenia and healthy participants. BMI was positively correlated with age and negatively correlated with gray matter volume and the ratio of gray matter volume in the healthy participants. No such correlations were found in the patients with schizophrenia. BMI were not correlated with the total score of PANSS, nor with the factor score of PANSS. Conclusion BMI is positive correlated with age, but negatively correlated with gray matter volume and the ratio of gray matter volume in healthy adult. But such correlations disappear in patients with schizophrenia. BMI is not associated with the seriousness of psychotic symptoms.