To overcome shortcomings and improve calculation accuracy of the common seismic fragility analysis method, the kernel density estimation method (KDE) is introduced and used to analysis the seismic fragility of bridge structures. A typical four span railway rigid frame-continuous beam bridge with high pier was taken as engineering case, and the fragility analysis of this bridge was carried out. The calculation result by using of KDE method was validated by using of Monte Carlo method, and then was compared with traditional methods (cloud method, maximum likelihood estimation method). Result shows that the KDE method could overcome the shortcomings of common fragility analysis methods of bridge and presents a good stability, and also improves the computational efficiency of seismic fragility analysis method on the premise of ensuring the accuracy. The calculation accuracy of cloud method is the lowest among of the using methods, and the KDE method was suggested to use for seismic vulnerability analysis of bridge. The seismic fragility curves could be applied to evaluate the performances of bridge seismic.