Objective To develop a questionnaire on the clinical first aid ability of cardiovascular internal medicine nurses，and to examine its reliability and validity，so as to provide a tool for evaluating the clinical first aid ability of cardiovascular internal medicine nurses. Methods Based on the competency iceberg model，an item pool of the questionnaire was formed based on literature review and group discussions. The questionnaire was drafted through two rounds of Delphi expert consultation. After that questionnaire was distributed among 239 cardiovascular internal medicine nurses from 10 secondary and above general hospitals in Liaocheng City in order to test the reliability and validity of the questionnaire. Results Through exploratory factor analysis，five common factors were extract，namely theoretical knowledge reserve，operational skills，first aid ability，communication and coordination ability，and occupational characteristics，with a cumulative variance contribution rate of 65.854%. A questionnaire with 25 items was formed，with an item level content validity index of I-CVI 0.875 to 1.000. The content validity index of the scale of S-CVI was 0.995. The Cronbach’s α coefficient of the questionnaire was 0.934，and the Cronbach’s α coefficient of each dimension ranged from 0.736 to 0.832. Conclusion The Questionnaire of Nurses’ Clinical First Aid Ability in Cardiovascular Department has good reliability and validity，which can be used to evaluate nurses’ clinical first aid ability in cardiovascular department.