The utility model discloses a thyristor valve for a high-voltage and dynamic reactive power compensator. An air cylinder is fixed to the middle of two vertical columns, a supporting block is connected between the vertical columns, and a pressing screw bolt is arranged at the middle of the supporting block. A bottom pressing block is firstly put in, then a thyristor and a radiator of the thyristor are arranged in turn in the air cylinder, an upper part pressing block then is put in, and the pressing blocks, the thyristor and the radiator are pressed by the pressing screw bolt and are made into one body. The utility model has the advantages that the thyristor valve has simple and practical structure, can lower rapidly the junction temperature of the thyristor below the safe temperature by forcing the air cooling, ensures the normal operation of the high-voltage and dynamic reactive power compensator, and ensures the produce power utilization.