The present disclosure relates to an active sonar system including a transmitter; a transducer; and an impedance matching circuit, and a method of estimating an equivalent model parameter of a multi-mode transducer, wherein an electrical equivalent model parameter having a plurality of stages corresponding to each mode is estimated by estimating an individual mode impedance and a total mode impedance from multi-mode impedance data and obtaining an interference amount of adjacent modes, and an equivalent model modeled thereby for which an interference effect by a multi-mode is taken into consideration is used for the design of an impedance matching circuit to minimize actual model fabrication and effectively derive detailed design elements and the like, thereby allowing an integrated circuit design with peripheral electronic units for interfacing the sonar system.