In order to investigate the correlation between angiotensin converting enzyme (ACE) and Schizophrenia, serum ACE activity of 326 schizophrenia cases and 298 control cases was detected by using Automatic Biochemical Analyzer continuous monitoring method, and the results were statistical y analyzed. The case-control study showed that normal controls and schizophrenia were no significant difference in serum ACE activity (p﹥0.05). There was no correlation between schizophrenia and serum ACE activity.