The invention discloses a cooling system for the whole cabinet of a server. The cooling system comprises a backboard, a plate type heat exchanger, a water pump, a temperature measurement device and a controller, wherein a cooling water channel is formed in the backboard, and is provided with a water inlet and a water outlet; a water inlet pipeline is connected between the plate type heat exchanger and the water inlet of the backboard, and a water outlet pipeline is connected between the plate type heat exchanger and the water outlet of the backboard; the water pump is arranged on the water outlet pipeline and/or the water inlet pipeline; the temperature measurement device is arranged on the water outlet pipeline; the controller is connected with the water pump and the temperature measurement device respectively. According to the cooling system, the controller can be used for controlling the working frequency of the water pump according to the temperature of return water flowing back from the backboard to the plate type heat exchanger; when the heating value of the whole cabinet of the server is greater, the working frequency of the water pump can be correspondingly increased so as to improve cooling effects and avoid damage to the server; when the heating value of the whole cabinet of the server is lower, the working frequency of the water pump can be correspondingly lowered so as to reduce the running energy consumption and the cost.