Abstract: Traditional polyurethane foam was not good at absorbing the low-frequency noise, so magnetic polyurethane foam (MPF) loaded with carbonyl iron powder (CIP) was presented by one-step full water foaming method. Sound absorption test-platform of MPF was built. The influence of both the ratio of polyether polyols and isocyanate and CIP on sound absorption properties was investigated from both macroscopic and microscopic view. The micro topography of MPF was observed through SEM, the cell size was analyzed using statistical method, and the sound absorption performance of 64-1 600 Hz was tested by impedance tube and the transfer function method. The results show that the addition of CIP makes the average pore size of MPF decrease, the logarithmic distribution standard deviation increase, the open rate increase and the low-frequency sound absorption performance improve, especially less than 500 Hz; when the ratio of polyether polyol and isocyanate is 100:60, with 5wt% CIP, the low-frequency sound absorption performance of MPF is optimal and the average sound absorption coefficient of 64-500 Hz is 0.22.