During the transportation of railway, all kinds of transportation equipment are subject to random vibration generated by random road excitation. In practice, however, a lot of vibration caused by poor environment of railway show non-Gaussian incentive features. Based on IFFT transformation-based of Gaussian random, by analyzing the relationship among phase angle, kurtosis and skewness, the paper uses the second phase modulation method to generate the non-Gaussian excitation signal with the measured vibration data in the process of train running, and then using MATLAB, this method will simulate the real railway vibration of non-Gaussian excitation signal. The simulation result provides the theory basis for the reliability verification of laboratory and shipping goods, and has a certain practical significance for the improvement of train operation safety.