Abstract: In order to make the microperforated plate sound absorber has low frequency and wide band sound absorption performance, a kind of microperforated plane absorber composed of rigid composite microperforated plate and flexible microperforated film is proposed in this paper, and its sound absorption effect is predicted by the average velocity method. The effects of film area proportion, film thickness and back cavity depth on sound absorption are analyzed, and the results show that: compared with the rigid microperforated plate sound absorber, the frequency bandwidth of sound absorption of the coupled microperforated plate sound absorber extends from 260 Hz to 650 Hz,and compared with the flexible microperforated plate sound absorber, the sound absorption coefficient increases from 0.55 to 0.75 in a certain frequency range. By appropriately changing the film thickness, the back cavity height and the film area proportion, the relative positions of the absorption peak of the microperforated plate and the resonance absorption peak of the film can be controlled, and a better sound absorption performance of the sound absorber can be obtained. The research results can further broaden the application range of microperforated plate sound absorber in the field of low frequency noise reduction.