This pilot study revealed that most vocational high school principals accept using 360 degree evaluation feedback as the mechanism for evaluating leadership effectiveness and as a reference for leadership behavior change intentions. However, whether this can cause behavior change or elevation of leadership effectiveness remains uncertain and must be tracked and verified. The current study continues previous research and has the following purposes: (1) to investigate the status quo of vocational high school principals' leadership effectiveness and the differences before and after implementing 360 degree evaluation feedback, (2) to analyze the relationship between principals' leadership behavior change intentions and their leadership effectiveness, and (3) to explore principals' opinions regarding use of the 360 degree evaluation as a motive for leadership behavior change and their perceptions of the influence on leadership effectiveness. To achieve purposes (1) and (2), this study examines the 69 schools in the pilot study and uses a sample of 40 schools and 1030 people for the questionnaire survey. The interview survey is conducted on 12 principals of the 40 schools for research purpose. (3) This study gains significant findings: (1) Vocational high school principals emphasize rational goal leadership effectiveness. (2) Implementation of 360 degree evaluation benefits principals in improving leadership effectiveness. (3) Principals with high behavior change intentions have better leadership effectiveness. (4) Principals mostly possess positive and supportive attitudes toward using 360 degree evaluation feedback as an important source of leadership behavior change, and they have positive perceptions of its influence.