The invention discloses a multi-target constraint extra-high voltage power grid voltage reactive power coordination control method and system. The method comprises the steps of: collecting operation data of a voltage reactive power regulation device of an extra-high voltage power grid in real time; determining the constraint condition and the control target of the operation data according to the system configuration parameters of the voltage reactive power regulation device; calculating the sensitivity of the voltage reactive power regulation device according to the operation data and the constraint condition; determining the voltage and the reactive power value required being regulated according to the difference between the operation and the control target; and determining a regulation control strategy according to the voltage and the reactive power value required being regulated and the sensitivity of the voltage reactive power regulation device. The method and system can be appliedto the power grid system simulation calculation to provide reference basis for a dispatcher to make an operation mode, can be applied to the system reactive voltage online analysis to provide an auxiliary decision for the dispatcher to adjust a reactive strategy.