Abstract: Objective: To develop an assessment scale of online self-regulated learning for nursing students and to test its reliability and validity. Methods: The initial scale was formulated through literature review and expert consultation. A total of 375 nursing students were investigated to screen items using critical ration, correlation analysis, Exploratory Factor Analysis (EFA) and internal consistency. A total of 527 nursing students were recruited to conduct formal investigation to evaluate the psychometric characteristics by Confirmatory Factor Analysis (CFA) and reliability test. Results: The formal scale included 36 items belonging to 8 dimensions. EFA revealed that 8 factors accounted for 63.331% of the accumulated variances. CFA indicated:χ2/df=2.345, RMSEA=0.051, GFI=0.862, NFI=0.862, IFI=0.916, TLI=0.904, CFI=0.915. The scale-level content validity index is 0.978. The criterion-related validity was 0.547 (P<0.01). The Cronbach's α coefficient was 0.931. The test-retest reliability was 0.816. Conclusion: As an instrument with good reliability and validity, this scale could be used to assess the condition of nursing students' online self-regulated learning.