A low-pass acoustic filter bank broadband sound absorber, comprising a micro-perforated plate, a micro-perforated plate rear cavity, an equal cross-section or variable cross-section meandering sound wave main channel that communicates with the plate rear cavity, and a plurality of low-pass acoustic filters that are arranged along the sound wave main channel in order of cut-off frequencies from high to low starting from an ingress of the sound wave main channel. One side of the micro-perforated plate is an incident end of an external sound wave, a cavity is arranged at the rear of the other side thereof, and the tail end of the cavity communicates with a start end of the sound wave main channel; a sound wave incident from the exterior enters the cavity at the rear of the micro-perforated plate by means of same, and then enters the sound wave main channel from the cavity; the meandering sound wave main channel is a tail end-closed, circuitous and curved channel that is closely arranged in a sound absorber as a single layer or multiple layers; and when the sound wave main channel is arranged as multiple layers, channels between adjacent layers communicate with one another so as to ensure that the sound wave main channel communicates from the start end to the tail end. In the low-pass acoustic filter bank broadband sound absorber, the use of one sound wave main channel to meet the requirements of a micro-perforated plate absorbing phase propagation delays of sound waves in different central frequency bands can be achieved and the meandering arrangement of the sound wave main channel is combined at the same time, and an ultra-thin structure size can also be achieved.