Music boundary detection is a fundamental step of music analysis and summarization. Existing works either use unsupervised or supervised methods to detect boundary. In this paper, we propose an integrated approach that takes advantage of both methodologies. In particular, a graph-theoretic approach is proposed to fuse the results of an unsupervised model and a supervised one by the knowledge of the typical length of a music section. To further improve accuracy, a number of novel mid-level features are develop and incorporated to the boundary detection framework. Evaluation result on the RWC dataset shows the effectiveness of the proposed approach.