The invention discloses an electro-catalysis treatment device for seawater circulation culture system. The electro-catalysis treatment device comprises a barrel, a water inlet, an air inlet, a water outlet and an exhaust opening, wherein the water inlet and the air inlet are located in the bottom of the barrel, and the water outlet and the exhaust port are located in the top of the barrel. Multiple carbon rods are arranged in the barrel and parallel to a barrel body, and the carbon rods extend above the water outlet from the water inlet. The parts between the carbon rods are filled with catalyst particles. According to the device, ammonia nitrogen and COD in seawater culture waste water can be effectively removed, the trouble caused by the high salinity of seawater is converted into advantages, the seawater circulation culture system is made to stably run, and the electro-catalysis treatment device is efficient, convenient to use, small in occupied space, economical and environmentally friendly.