Vibroacoustic coupling systems widely exist in various engineering fields, and controlling their vibration and noise is essential. Unfortunately, the existing literature lacks research on the vibroacoustic coupling system composed of multi-plates and a cavity with nonlinear factors, limiting the application of nonlinear factors in controlling the vibration and noise of the vibroacoustic coupling system. This work aims to explore the effect of the nonlinear layer on the behavior of a vibroacoustic coupling system, where the behavior of the vibroacoustic coupling system motivated by the nonlinear layer and the vibroacoustic behavior under constant frequencies caused by the nonlinear layer is systematically studied. It can be found that the behavior of the vibroacoustic coupling system with a nonlinear layer can be correctly predicted by using the Lagrange method. The nonlinear layer establishes a new vibration-converting pathway of the vibroacoustic coupling system. A reasonable nonlinear layer is suitable for controlling the vibration of plate 2 and the sound pressure of the cavity. In a reasonable variation range, adjusting key parameters of the nonlinear layer is a feasible way to artificially control the unconventional responses under constant frequencies of the vibroacoustic coupling system. Overall, the introduction of the nonlinear layer provides a possible approach to control the vibroacoustic coupling system’s behavior, providing a new perspective to utilize the nonlinear layer in controlling the vibroacoustic coupling system.