The purpose of this study is to ascertain the relationship between the leadership behavior of senior high school principals and the morale of the teachers under their leadership. For this purpose, survey and analysis methods were used, and two questionnaries, entitled "Principals' Leadership Behavior Description Questionnaire" and "High School Teachers' Morale Description Questionnaire," were distributed to 1,553 teachers who teach in 155 senior high schools all over Taiwan. After these questionnaires were collected, statistic method was used to ascertain the relationship between the principals' leadership styles and the teachers' morale in senior high schools in Taiwan. The findings are as follows: 1. The initiation behavior of senior high school principals varies with the nature of respective schools. The principals of vocational senior high schools get the highest scores, followed by the senior high schools which have vocational training departments. Ordinary senior high schools rank the third, and special-education schools get the lowest scores. 2. Teachers of the ordinary high schools seem to have the highest morale, and those who teach in special-education schools have the lowest morale. Teachers' morale is also in proportion to the size of schools where they teach. The bigger the school in which the teacher teaches, the higher his morale will be. Further more, female teachers' morale is higher than male teachers'. 3. The leadership behavior of most senior high school principals is the "high initiating structure, high consideration" style, which far exceeds the "low initiating structure, low consideration" pattern. 4. There is a positively close relationship between senior high school principals' leadership behavior and teachers' morale. 5. Senior high school principals' consideration behavior is the best predicator of teachers' morale.