Music is inherently abstract and multidimensional. However, existing music search engines are usually not convenient or too complicated for users to create multidimensional music queries, leading to the intention gap between users' music information needs and the input queries. In this paper, we present a novel content-based music search engine, the Intelligent & Interactive Multidimensional mUsic Search Engine (i 2 MUSE), which enables users to input music queries with multiple dimensions efficiently and effectively. Six musical dimensions, including tempo, beat strength, genre, mood, instrument, and vocal, are explored in this study. Users can begin a query from any dimension and interact with the system to organize the query. Once the parameters of some dimensions have been set, i 2 MUSE is able to intelligently highlight a suggested parameter and gray out an un-suggested parameter for every other dimension, helping users express their music intentions and avoid parameter conflicts in the query. In addition, i 2 MUSE provides a real-time illustration of the percentage of matched tracks in the database. Users can also set the relative weight of each specified dimension. We have conducted a pilot user study with 30 subjects and validated the effectiveness and usability of i 2 MUSE.