Objective To investigate the matching of dementedness’TCM syndrome differentiation and severe mental disorders’diagnosis in western medicine with The Software on The Diagnosis and Public Safety Risks Evaluation of Psychiatric Patients in Community after TCM syndrome differentiation. Methods 200 demented patients or severe mental disorders who meet the criteria of TCM and has one description of community severe psychiatric disorders index is recruited. Two psychiatrists of TCM practitioners diagnose them and differentiate their disease according the clinical manifestation and tongues and pulses with reference to internal TCM，then testing of the software questionnaire to the persons concerned and persons in the know. Results ①184 of 200 recruits had completed effective test and the completion rate is 92%. The result of software testing to 184 demented patients after the diagnosis of TCD shows following percentage：schizophrenia 54. 89%，bipolar disorder 20. 11%，persistent delusional disorder 14. 13%，depression 8. 15%，schizoaffective disorder 2. 72%，and the other 6. 67% are not severe FMDs. Dementedness’tcm syndrome differentiation to the FMDs shows the following percentage：stagnation of phlegm and QI 27. 22%，interior disturbance of the phlegm-heat 20%，insufficiency of heart and spleen 16. 11%，Fire Yin 11. 11%，Stagnated heat 6. 67%，the rest syndrome type 14. 44%，and no syndrome 6. 67%. ②TCM syndrome differentiation of severe mental disorders，schizophrenia represents stagnation of phlegm and QI，most patients of persistent delusional disorder and schizoaffective disorder show interior disturbance of the phlegm-heat，bipolar disorder people have the characteristics of either Fire Yin or interior disturbance of the phlegm-heat，above disease have statistical significance（P<0. 05），but the patients of depression have less statistical significance although they have the disease of insufficiency of heart and spleen（P＞0. 05）. Conclusion By the comparision between personal TCM syndrome differentiation and the diagnosis of The Software on The Diagnosis and Public Safety Risks Evaluation of Psychiatric Patients in Community，we are sure that dementedness’tcm syndrome differentiation is in large matching to severe mental disorder in western medicine，but the scope of concept ot dementedness is larger than that of severe mental disorder and the 20% patients of severe mental disorder are not demented. Thus these two concepts are different and cannot replace each other.