A thyristor valve photoelectric trigger plate for a static reactive power compensator is composed of a voltage power-fetch and a supply conversion circuit, a supply monitor loop, a voltage testing loop, a logic circuit, a trigger circuit, a back-up trigger circuit, a light receiving loop and a light emit circuit, among which, the voltage power-fetch and supply conversion loop gets power supply necessary for the system work from a primary device, the logic circuit coordinates work of all parts to encode and decode signals to generate trigger pulses and state signals to generate trigger pulses and state information of the thyristor, the back-up trigger loop trigger the thyristor valve automatically when over high voltage appear at both ends of the valve to avoid broken-through.