The invention discloses a wheel polygon identification method based on wheel-rail vertical force and a device thereof. The wheel polygon identification method comprises the following steps that a wheel-rail vertical force signal is collected through a shear stress method; EEMD is conducted on the collected wheel-rail vertical force signal, so that a lumped IMF component is obtained; an IMF marginal spectrum comprising characteristic information of wheel polygon defects is calculated; and a damage characteristic frequency F is obtained according to the obtained the IMF marginal spectrum, and whether a wheel appears polygon and polygon types or not is identified according to the preset criterion. The wheel polygon identification method has the advantages that real-time monitoring and damageevaluating can be conducted on vehicles passing through a monitored road section, and the characteristics of rapidity and precision are achieved; and the time-varying wheel-rail vertical force signalcan be processed very well through the EEMD method, and the wheel-rail vertical force damage characteristic frequency after the polygon defects appears in the wheel is obtained by calculating and decomposing the marginal spectrum of the signal.