Objective To explore the level of core competency of chief resident nurses and its relationship with professional calling, and to provide a reference for improving the core competency of chief resident nurses.Methods A total of 293 resident nurses were selected from five hospitals in Guangdong province using convenience sampling method and were asked to complete the Competency Inventory for Registered Nurses and the Chinese Calling Scale.Results The total competency score was （146.09±39.20） and the total calling score was （39.18±7.15）, showing a significant positive correlation between them (P＜0.05).Hierarchical regression analysis showed that after controlling for demographic variables, professional calling explained 38.5% of the total variance in resident nurses′ core competency.Conclusion The core competency of resident nurses is at moderate level and affects by their professional calling.Nursing managers should develop effective training strategies to enhance resident nurses′ professional calling and core competency.