The invention discloses a performance analysis method of a saturated reactor for a converter valve in a thyristor impedance state, particularly to the performance analysis of the saturated reactor in the impedance state comprising a forward impedance state and a backward impedance state of a protection thyristor. The converter valve needs to bear impacts in the types of operation, thunders and steep waves, under the working conditions, the thyristor is in the impedance state, and in the states, the target of greatly sharing the voltage strength applied to the thyristor can be achieved by regulating the electric parameter of the saturated reactor. According to the safety operation area of the thyristor in the impedance state, the thyristor is reasonably converted into a voltage strength curve in a transient state, and the relation between the parameter of the saturated reactor and the target of the protection thyristor thereof can be obtained through frequency-domain analysis. The analysis method provided by the invention has simple operation, clear physical conception and intuitive analysis result and lays theoretical and simulation foundations for further realizing the electric parameter design of the saturated reactor in the thyristor impedance state.