OBJECTIVE To develop and validate a self-rated scale for evaluating the core competencies of clinical nurse educator (CNE). BACKGROUND The competency of CNE is critical in ensuring the quality of clinical internship training and lifelong nursing education. Currently, we lack validated evaluation tools to measure CNE's competency. METHODS Scale development and validation. METHODS Guided by core competency theory and previous constructed Chinese CNEs' core competency, a draft scale was constructed in October 2023 after literature review. Through Delphi consultation from January to May 2024, the initial version of the scale was developed. Following a pilot survey in May 2024, through data collection from June to July 2024, the scale was refined using item analysis, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). RESULTS Data from 601 CNEs were analyzed. The final 35-item scale comprised four dimensions: clinical nursing skills (7 items), clinical teaching competency (9 items), management and leadership competency (15 items) and innovation and research competency (4 items). Item was rated on a 5-point Likert scale. The scale demonstrated strong psychometric properties: total Cronbach's α = 0.975 (subdimensions: 0.870-0.966), split-half reliability = 0.940, test-retest reliability = 0.833 and content validity index = 1.00. CFA results confirmed acceptable model fit (χ²/df = 2.023, RMR = 0.022, RMSEA = 0.059, TLI = 0.931, CFI = 0.937). CONCLUSIONS The developed scale exhibits robust reliability and validity, providing a scientifically grounded tool for self-assessing CNEs' core competencies. It may be a reference for CNE selection, training and evaluation in clinical settings.