Abstract: In this paper, the air duct of the frost-free refrigerator is taken as the research object. The natural frequency analysis, harmonic response analysis and LMS Test.Lab vibration test of the air duct are conducted by finite element simulation, and the natural frequency, amplitude limit and experimental mode of the air duct shell are obtained. The calculation results show that the frequency of the strongest vibration of air duct is close to the fundamental frequency of the fan, and the vibration amplitude can be reduced by pasting damping materials on the air duct, thereby the radiation noise transmitted from the duct shell to the refrigerator box is reduced. The experimental results show that after the damping materials are pasted on the area of the air duct shell with the largest vibration amplitude, the vibration of the whole refrigerator is obviously weakened and the radiated noise level is reduced by 1.9 dB according to the test in a semi-anechoic chamber. This paper provides a direction and suggestions for reducing vibration and noise in air duct.