To efficiently solve the fifth-order Korteweg-de Vries (KdV) equation commonly used in the field of physics, a study was conducted on the solution methods for five different types of fifth-order KdV equations. A class of space-time polynomial method of particular solutions was proposed, and the numerical results of this method were compared and analyzed with those of the Fourier spectral method. The research results show that this proposed method has significant advantages in solving the fifth-order KdV equation: by selecting appropriate polynomial basis functions, this method effectively avoids the difficulty in evaluating high-order linear derivative terms in the governing equation and significantly improving the computational efficiency; at the same time, due to the application of the multiscale technique, it greatly reduces the condition number of the coefficient matrix and further improves the computational accuracy. Therefore, the space-time polynomial method of particular solutions can effectively solve various types of fifth-order KdV equations, providing reliable methodological support for its practical engineering applications, and holds important theoretical and practical significance.