Abstract: As a result of the " openness”of the stipulation for the election of the Holy Roman Emperors, which was provided in Golden Bull of 1356, the election of the Holy Roman Emperor in 1519 attracted quite a few candidates. The powerful Karl Ⅴ. won the election finally. The Prince-electors reached a " political consensus” and believed that it was necessary to set and regulate the power of the powerful emperor. Karl Ⅴ. was required to sign the Electoral Capitulation and to make a solemn vow that the Electoral Capitulation will be observed. Hereafter, every newly-elected emperor had to sign an Electoral Capitulation. Since the election of Karl Ⅵ. in 1711, the Electoral Capitulation has transformed from " political consensus” to " consensus politics” and become " leges fundamentales”of the Holy Roman Empire from a political contract with " chanciness”. On the basis of rational discussion and the compromise of interests, the Prince-electors reached the " political consensus”, and on the basis of " political consensus”, the Prince-electors had the regulatory awareness and rights consciousness. The Electoral Capitulations are not only the achievement of the " political consensus” but also the reflect of the " consensus politics” and the foundation of the legitimacy of the newly-elected emperor. In the process of the development of history, they have the meanings of " modern” constitutional significance and institutional implication.