Objective To investigate current situation of core competencv of intravenous therapy (IV) among nurses from member hospitals of medical alliance, to analyze the influencing factors, to provide references for rejigs in IV training programs across the member hospitals of medical alliance, and to improve nurses′ core competence. Methods A convenience sampling method was used to select 2 405 nurses from 8 member hospitals of a medical alliance.They were surveyed using the general information questionnaire, the Nurse Intravenous Therapy Core Competency Assessment Scale and the General Self-Efficacy Scale. Results The total score of IV core competency averaged (115.67±22.78) points, and the total score of general self-efficacy averaged (32.20±6.13) points.Multiple linear regression analysis showed that, whether or not having attended IV training programs and general self-efficacy were influencing factors of nurses′ IV core competency （P＜0.05 for both）, with the 2 variables explaining 43.0% of the total variation. Conclusion The IV core competency of nurses from member hospitals of medical alliance was slightly above medium level.Nurses who had attended IV training programs or had higher level of self-efficacy tended to have higher level of IV core competency.It is recommended that hospital managers should ramp up trainings for nurses, and take measures to strengthen their self-efficacy, so as to improve nurses′ IV core competency.