This study was conducted to improve the quality of National Health Policy by analysing the effects of sociodemographic characteristics , Medical institutions characteristics and characteristics of Admission-Discharge on the length of stay in hospital for schizophrenic patients from the data of Health Insurance Review & Assessment Service. The subjects were 4,692 patients who were diagnosed with schizophrenia as main diagnosis from the data records of HIRA-NIS 2016. Regression analysis was performed to evaluate the effect on the length of stay. Sociodemographic characteristics , hospital characteristics and characteristics of Admission-Discharge were used as explanatory variables and length of stay in hospital was used as a dependent variable. The result of study showed that female, age, medical aid, the kind of hospital, gangweon-do and with mental disease were found to be the factors that affect the length of stay. The significance of this study is to use the public data for evaluating factors that affect the length of stay in hospital for schizophrenic patients. But this study did not consider disease severity, so further study is needed for evaluation of the effects of factors on the length of stay according to disease severity.