In this paper, we propose a music search system that offers query-by-multimedia mechanisms for constructing a database query as a combination of musical data such as music data, attributes of music, several impressive colors, and keyword tags. This system provides a query construction model to generate sequential query conditions for evaluating time-dependent status of the musical contents. Queries of this system consist of multiple query conditions that are sequentially located on the timeline of target music data. The system provides a set of operators to construct the query by combining multiple multimedia data. Our query construction model allows characterizing the significance of music data, through the combination of multimedia data. A unique feature of this system is that it offers a sophisticated music database environment including a GUI system for a query editor and a result browser. Our GUI system has customizable visualization mechanisms that make it possible to display continuous contents such as our queries and music data. We clarify the feasibility of the system by showing several experimental results.