This paper present the transient stability analysis of a power grid, which integrates both superconducting magnetic energy storage (SMES) and gridable vehicles (GVs). Also, vehicle-to-grid (V2G) operation is devised to control GVs to charge from or discharge to the grid. Simulations of various faults are carried out under different penetration proportions of SMES and V2G power. The results of load angle response and system voltage response are given to illustrate that both SMES and GVs can enhance transient stability of the power grid. Moreover, the simultaneous use of SMES and GVs can further improve the system dynamic performances.