Quantitative studies using validated questionnaires on core competencies of emergency nurses in China are rare and the baseline core competencies must first be evaluated before improvizations to the competencies can be implemented. This study aimed to investigate the factors potentially involved in the level of core competencies of emergency nurses from tertiary hospitals in northwest China.In this cross-sectional study, male and female emergency nurses (n = 277) from tertiary hospitals of northwest China were enrolled to complete the Competency Inventory for Registered Nurses (CIRN) questionnaire comprising of a total of seven dimensions with 58 items. General self-efficacy and perceived stress were also evaluated. Pearson correlation test and multivariate stepwise linear regression analysis were performed to assess the association between various factors associated with core competencies.Senior nurses had higher CIRN scores than junior nurses (p < .001). Married and widowed nurses had higher CIRN scores than unmarried and divorced nurses (p = .008). Nurses satisfied with their career had better CIRN scores than those who were dissatisfied (p < .001). CIRN scores were correlated with age (r = .356, p < .001), working years (r = .374, p < .001), and the general self-efficacy scale (r = .547, p < .001). Multivariable stepwise linear regression analysis showed that higher professional titles and job satisfaction were independently associated with higher CIRN scores (both p < .001).Emergency nurses from tertiary hospitals of northwest China with senior titles and job satisfaction had high CIRN scores which necessitates empowering the junior nurses by way of education and training programs to gain higher core competencies in order to deliver better nursing care to patients.