The invention discloses an electrical switch cabinet cooling system and a control method. The system comprises a mechanical ventilation cooling subsystem, a forced oil circulation subsystem and a cooling control subsystem, wherein the mechanical ventilation cooling subsystem comprises an axial flow fan, a sealed air duct, an electric control baffle and a fresh air duct, and the sealed air duct isconnected with the air inlet side and the air outlet side of the switch cabinet body to form a closed circulating air duct; the fresh air duct is obliquely connected to the sealed air duct in a branched mode in the ventilation leading direction; the forced oil circulation cooling system comprises a circulating oil pump, an oil cooling coil, a buffer liquid tank, an electric control regulating valve and a plate heat exchanger, and is formed by connecting circulating oil pipelines; the cooling control system comprises a cooling controller, a control bus, a gas concentration measuring meter and atemperature measuring meter, and the cooling controller, the gas concentration measuring meter and the temperature measuring meter are all in electric signal connection with the control bus. The system is simple in structure, mature in technology, low in failure rate, high in reliability, low in manufacturing cost, and simple in daily operation and maintenance.