The purpose of the study was to construct the criterion and standard of professional development of principals in junior high school and senior high school. The study employed questionnaire surveys. Data were collected from principals and experts with questionnaire surveys. In short, the study constructed the 7 levels, 47 criteria, including school development, administration and management, curriculum and instruction, and so on.Based on the result, the research tried to make suggestions for curriculum design and training program for principalship.