The invention discloses a method for solving lateral oscillation frequencies of inhaul cables under any boundary constraint condition. The method comprises the following steps of: firstly establishinga lateral oscillation functional of an inhaul cable; solving the lateral oscillation functional of the inhaul cable by adoption of a Chebyshev series method so as to obtain a lateral oscillation circular frequency of the inhaul cable; and finally calculating a lateral oscillation frequency f of the inhaul cable through a formula f=/2. In the process of constructing the lateral oscillation functional, boundary constraint parameters at two ends of the inhaul cable are set; after boundary constraint conditions at the two ends of the inhaul cable are obtained, the boundary constraint parameters at the two ends of the inhaul cable can be obtained to be used in the lateral oscillation functional of the inhaul cable; and in the process of solving the lateral oscillation functional ofthe inhaul cable by adoption of the Chebyshev series method, a feature matrix equation of the inhaul cable is obtained through selecting a proper inhaul cable lateral oscillation displacement distribution function, and the lateral oscillation circular frequency of the inhaul cable is obtained through solving the feature matrix equation. The method has the advantages of being relatively small in error and relatively high in precision on the basis of a simple solution process.