This paper proposes a simulation method of the internal winding fault to calculate the short-circuit current, electromagnetic force and vibration mode in a distribution power transformer by suing FEM and analytic algorithm. A usage of the pseudospectral method is also presented for the vibration analysis of the winding during the short-circuit. The equations of the winding are approximated by the series expansions of Chebyshev polynomials and the Gauss-Lobatto collocation process is performed. The simulation examples are provided for the cable type winding of the transformer(22.9 kV/220 V, 1000 kVA) to verify the method. The simulation results are in good agreement with FEM solutions and analytical methods.