Objective To develop a scale to measure family involvement and willingness toward institutionalized care and to test the reliability and validity. Methods The draft scale was formulated based on literature review, semi-structured interview and two-round expert consultation using Delphi technique, then 326 family members of elderly persons living in 6 elder-care institutions in Zhengzhou were surveyed to test the reliability and validity. Results The formal scale consisted of 32 items assessing behavior subscale and willingness subscale of family involvement in institutionalized care. Six factors were identified in each subscale by exploratory factor analysis, accounting for 66.054% and 72.643% of the total variance. The Cronbach′s α coefficients for two subscales were0.950 and 0.941 respectively, and the 2-week test-retest reliability were 0.905 and 0.960. Conclusion The family involvement and willingness toward institutionalized care scale has good reliability and validity and can be used to evaluate the behavior and willingness of the family to participate in institutionalized care.