The invention provides a harmonic analysis modeling method of a power quality simulated analysis system of an urban railway system, including steps of step 1, structuring a power supply system simulation module of the urban railway system; step 2, structuring a simulation module of a train running status of the urban railway system; step 3, structuring a FFT harmonic analysis module for analyzing and comparing the harmonic wave information received by a wave recorder of the simulation module of the train running status of the urban railway system. The method can simulate the harmonic wave influence of running states of the simulation module of the urban railway systems under three working conditions (traction, idling and brake) on the power grid, thereby providing an analysis basis for better power quality.