This study is aimed to analyze the ultimate state of bridges with rocking isolation of spread foundations under extreme earthquakes. The Vector Form Intrinsic Finite Element method (VFIFE) is adopted to simulate the failure procedure of bridges with and without rocking isolation. To simulate the highly nonlinear behaviors between soil and foundations, Winkler-based models are established in the VFIFE in this study. A practical five-span bridge with spread foundations is chosen to study the effect of rocking isolation and discuss the influence of altering parameters of bridges. The analytical results are compared between linear soil springs and nonlinear soil springs. Furthermore, the ultimate state of bridges is simulated to realize the dynamic behaviors of bridges under extreme earthquakes.