The utility model specifically relates to an outdoor three-phase load imbalance automatic adjusting device heat radiation device comprising a cabinet body, and a surge protector and a molded case circuit breaker are fixedly arranged at the upper part in the cabinet body; a cabinet door is arranged in front of the cabinet body; wherein the upper end of the cabinet body is provided with an upper airduct, and the lower end is provided with a lower air duct; the upper air duct and the lower air duct are both of a box-type structure. Vent holes are formed in the left and right side walls of the upper air duct; the bottom of the lower air duct is open; a through hole is formed in the connecting position of the upper air duct and the top of the cabinet body; a first filter screen is arranged onthe upper through hole; a lower through hole is formed in the connecting position of the lower air duct and the cabinet body; a second filter screen is arranged on the lower through hole; and a fan isfixed below the first filter screen. According to the utility model, the upper air channel is communicated with the lower air channel, and the fan drives air in the cabinet to flow so as to take awayheat energy generated by power elements in the cabinet.