This paper proposes a combined index for voltage resilience in electric power system. This index consists of the minimum eigenvalue of reduced Jacobian matrix from the power flow calculation equations and the L-index deducted from voltage calculation equations, taking the voltage stability of whole system as well as that for individual buses into consideration. Simulation studies have been made using IEEE 30-bus system and a real power grid model, proving that this index for voltage resilience can effectively reflect the voltage stability variation under different load levels.