Objective To determine the level and factors associated with core competencies of primary health care nurses and to provide a reference for targeted interventions. Methods A survey was conducted on 1,845 nurses from 388 township health centers and 164 community health service centers in Ningxia autonomous region using a demographic data questionnaire and the core competency scale for community nurses. Results The total core competency score was (123.23±34.53), with the highest score on ethical and legal practice （2.61±0.71） and the lowest score on assessment and intervention (2.31±0.73). Classification tree model showed that work stress, out-of-hospital study plan, educational background, and frequency of night shifts were the main influencing factors of nurses′ core competency (all P＜0.05). Conclusion The core competency of primary health care nurses is at a medium level, which is mainly affected by work intensity and knowledge.Targeted intervention and support should be given to improve their core competency.