Objective To develop a Knowledge, Attitude and Practice Questionnaire for Prevention of Disability in Elderly Patients, and to test its reliability and validity. Methods Based on the theory of Knowledge, Attitude and Practice，a Knowledge, Attitude and Practice Questionnaire for Prevention of Disability in Elderly Patients was developed after literature review, expert consultation and pre-survey, then it was used to investigate 353 elderly inpatients or outpatients in a tertiary hospital in Wuhan from February to July 2023 to test its reliability and validity. Results Six common factors consisting of 26 items were extracted via exploratory factor analysis,with a cumulative variance contribution rate of 66.424%.The I-CVI ranged from 0.889 to 1.000, and the S-CVI/Ave of the questionnaire was 0.985. Confirmatory factor analysis result indicated good model fit.The overall Cronbach′s α coefficient was 0.912, the split-half reliability was 0.780, and the test-retest reliability was 0.947. Conclusion The questionnaire has good reliability and validity, and it can be used to evaluate the current status of knowledge, attitude, and practice of elderly patients regarding disability prevention.