The present invention relates to a converter valve cooling control system. The converter valve cooling control system comprises an inner cooling control system and an outer cooling control system, the inner cooling control system comprises a CPU and an inner cooling photoelectric communication module, and the outer cooling control system comprises an outer cooling photoelectric communication module, an interface module and an output module. The CPU controls and is connected with the output module via the inner cooling photoelectric communication module, an optical fiber, the outer cooling photoelectric communication module and the interface module, and the outer cooling control system also comprises a detection control relay KS and an intermediate relay. A normally-closed contact of the detection control relay KS drives and is connected with the intermediate relay, and a normally open contact of the intermediate relay is used to control and connect an auxiliary power supply branch of an AC load. When the sending communication of the inner cooling system and the outer cooling system goes wrong, the detection control relay is power-off, and the normally-closed contact of the detection control relay is closed, so that the AC load is in live-line operation, a spraying pump and a cooling fan entre a working state, and the stability and the reliability of a converter valve water-cooling system are improved.