Objective To develop a Knowledge, Attitude and Practice Scale for the prevention of deep vein thrombosis in patients treated with artificial liver support system(ALSS), and to test its reliability and validity. Methods Based on the theory of knowledge, attitude and practice as well as the results of telephone interviews with patients undergoing artificial liver treatment, the initial scale was constructed through literature review, Delphi expert letter consultation and pre-investigation.The reliability and validity of the scale were tested on 183 patients who received artificial liver treatment, resulting in the formation of the final version of the scale. Results The scale consisted of 27 items in 3 dimensions.The content validity index at the item level ranged from 0.889 to 1.000, and the average content validity index at the scale level was 0.933.Exploratory factor analysis extracted three common factors from each dimension of attitude and practice, and the cumulative variance contribution rates were 65.019% and 54.886%,respectively.The Cronbach′s α coefficient of the scale was 0.815, the split-half reliability was 0.834, and the test-retest reliability was 0.886. Conclusion The scale exhibits good reliability and validity, making it an effective tool for evaluating the prevention of deep vein thrombosis in patients treated with ALSS.