Purpose : This study was conducted to investigate the extent to which the professional self concept between the psychiatric mental health nurse practitioner (PMHNP) and general nurse in psychiatric ward was comparable. The results were expected to provide basic data for developing the construct of professional self concept and making awareness of the importance of the program increasing professional self concept. Method : The subjects of this study were 227 PMHNP and 436 general nurse in psychiatric ward. The instruments used for this study were PSCNI by Arthur (1990), PSI by Heppner and Peterson(1982) and the index of work satisfaction by Slavitt et al.(1978). With the aid of the SAS, t-test. two-way ANOVA and stepwise multiple regression were conducted. Result : 1. The average item score of PSCNI of PMHNP was $2.82pm0.27$. and that of general nurse was $2.66pm0.27$. Statistically significant difference between two groups was found(p=0.0000) 2. There was statistically significant difference between two groups in the score of professional practice(p=0.0000), satisfaction(p=0.0024), leadersbip(p=0.0000) , flexibility(p=0.0000) and skill (p=0.0000). 3. Statistically significant differences between the two groups were observed in terms of age(p=0.0003), marital status(p=0.0001). education(p=0.0005), religion(p=-.0144), motive (P=-.0001), length of service as a nurse(p=0.0121), the length of service in psychiatric unit(p=0.0143). However there were no significant interaction effect with group and age, marital state. education, religion, motive, length of service as a nurse, length of service in psychiatric unit. 4. Job satisfaction (JS) and problem solving inventory score(PS) were found to be the highest factor predicting the professional self concept between the PMHNP and general nurse. JS and PS accounted for $43.4\%$ in the professional self concept of PMHNP, whereas PS, JS, age and religion accounted for $53\%$ in the professional self concept of general nurse in psychiatric ward. In conclusion, this study suggested that we need to develop programs and polices to increase the professional self concept of nurse, particularly of psychiatric mental health nurse practitioners.