A muffling device and refrigerating and freezing apparatus. The muffling device, comprising a muffling body, the muffling body having a sound ingress and egress surface, at least one muffling chamber is provided inside the muffling body , the sound ingress and egress surface is provided with at least one communication port, each of the communication port connecting one or more of the muffling chamber, each of the muffling chamber is connected to the outside of the sound ingress and egress surface through at least one of the communication port. In the muffling device and refrigerating and freezing apparatus, when noise passes through the through-holes of the muffling device, the sound is transmitted through the communication ports into the muffling chamber, extending the sound propagation path, weakening the sound energy, and thereby reducing the sound that continues to disperse outward. Specifically, the length of at least one muffling chamber is between 0.0085m to 0.85m. The length of the muffling chamber is set so that the incident sound waves and reflected sound waves at the communication ports of the muffling chamber overlap, with the amplitudes being as equal as possible and the phases being inverted by 180° as much as possible, thus maximizing the cancellation of sound waves to achieve the purpose of muffling or noise reduction.