Objective To construct a competency model of hospital nurse assistants based on behavioral event interviewing and expert consultation method, and to provide reference for the selection of excellent hospital nurse assistants. Methods With literature review method, the first draft of the competency dictionary for hospital nurse assistants was compiled. The dictionary was modified and refined by using pilot interviews and expert consultation method. Behavioral event interviews were conducted among 20 hospital nurse assistants from 7 hospitals in Shanghai to extract and identify the excellent competency features from outstanding hospital nurse assistants, and to construct a competency model of hospital nurse assistants. Results In the interview texts, the 28 competency features appeared 92-184 times. The average grade scores were between (2.19±0.70) and (2.78±0.82). The average grade scores of 4 competency features, and appearance counts of 13 competency features were positively correlated with the length of the interview respectively(P<0.05 for all). The average grade scores of 9 competency features in the outstanding hospital nurse assistants were significantly higher than ordinary ones (P<0.05，P<0.01). The finalized competency model of hospital nurse assistants includes four dimensions of professional service characteristics, professional knowledge and skills, personal characteristics, and emergency rescue ability, totaling 28 competency features, among which, 9 are excellent features and 19 benchmark features. Conclusion The competency model of hospital nurse assistants is feasible and scientific. Among the 28 competency features, 19 benchmark features serve as the minimal qualities that ordinary hospital nurse assistants must possess, while 9 excellent features help set the bar for selection of outstanding hospital nurse assistants.