The invention relates to an equivalent time-domain model establishing method considering interaction of soil and fan system power. The equivalent time-domain model establishing method comprises the following steps of S1, standardizing the vibration impedance of the interaction of soil and fan basic power, and expressing into dynamic compliance; S2, utilizing a Chebyshev complex polynomial to fit the dynamic compliance, expressing into a recursive function type, establishing a recursive physical model for expressing the interaction of soil and fan basic power, and determining to-be-determined coefficients of springs and dampers in the recursive physical model; S3, establishing the equivalent time-domain model considering the interaction of soil and fan system power. The equivalent time-domain model establishing method has the advantages that when the response of a fan system considering the interaction of soil and basic power under the horizontal excitation is calculated, because the recursive physical model does not contain mass elements, the correction of inputted basic horizontal power load is not needed, and the model is more directly and conveniently applied in actual engineering; by utilizing the recursive property, a motion control equation of the fan system has regularity, and the solving procedure is well universal.