This paper proposes a mechanically coupled resonance muffler on the base of a traditional Helmholtz resonator， which can improve the acoustic performance of the traditional one. The resonator has a flexible panel decorated with asymmetric mass blocks installed in its cavity， which divides the cavity into two. The incident acoustic wave excites the vibration of the flexible plate， which makes the plate coupled with the upper and lower cavities to form a new two-degree-of-freedom system， and splitting the resonant peak of the traditional Helmholtz resonator into two. Based on the theoretical analysis of the simplified coupled resonance muffler， mass blocks are added to the flexible plate to make its vibration behavior more adjustable. Meanwhile，the influences of the structural parameters on the acoustic characteristics of the muffler are analyzed qualitatively by a finite element analysis software. Finally， experimental studies are carried out to verify the validity of the above works.