Objective To understand the current situation and relationships of core competency, self-efficacy and self-directed learning ability in clinical nurses, and to explore the influencing factors of their core competency, so as to provide evidence for developing core competency training programmes for clinical nurses. Methods Convenience sampling method was used to select and survey 605 clinical nurses from 2 tertiary general hospitals in Yanji city, then they were investigated by utilizing a general information questionnaire, Competency Inventory for Registered Nurse (CIRN), the General Self-Efficacy Scale(GSES), and the Adult Learning Traits.Results The participants′ score of core competency was 3.56±0.83, self-efficacy was 2.70±0.66, and self-directed learning ability was 3.68±0.79; their score of core competency was positively correlated with the scores of self-efficacy and self-directed learning ability (both P<0.05); self-efficacy, self-directed learning ability, and years of nursing work were the main influencing factors of core competency in clinical nurses (all P<0.05), which explained 45.9% of the total variance. Conclusion The core competency of clinical nurses in Yanji area is at a high level, and its main influencing factors are self-efficacy and self-directed learning ability. Nursing managers should cultivate clinical nurses′ self-efficacy and self-directed learning ability, so as to improve their core competency.