A certain type of centrifugal fan was taken as the research object, aimed at the coupling vibration problem of the fan impeller when rotating, the large eddy simulation method was used to carry out numerical analysis for the internal flow field law of the fan, and the results were compared with those of RNG κ-ε model. The unidirectional fluidsolid coupling analysis for the fan impeller was carried out by using the numerical analysis results of the large eddy simulation. The results show that the analysis results obtained by using the large eddy simulation are more accurate and can better represent the real flow conditions inside the fan; in terms of flow field, the pressure on the blade surface can fluctuate irregularly with time; in the aspect of statics, the equivalent stress is mainly concentrated in the middle of the blade and the contact part with the front and rear cover plates, and the deformation in the middle area of the impeller blade is large.