A centralized cooling system for a data center, characterized in that, it comprises at least one cabinet, a spray hydraulic device and a hydraulic working substance cooling equipment which are integrated outside the cabinet, and an outer liquid working substance tank, wherein the spray hydraulic device, the hydraulic working substance cooling equipment, the outer liquid working substance tank and the cabinet are connected by a pipe, wherein the cabinet comprises an auxiliary cabinet, a server cabinet, liquid inlet pipes, and return pipes; wherein an inner liquid working substance tank, a main pipe and a pipe distributor are arranged inside the auxiliary cabinet, wherein the pipe distributor is in communication with the inner liquid working substance tank by the main pipe, and both the outer liquid working substance tank and the inner liquid working substance tank are loaded with insulative and thermally-conductive liquid working substance; wherein a server and a plurality of spraying mechanisms are arranged inside the server cabinet, and the spraying mechanisms are disposed directly facing a heat source of the server; wherein the spraying mechanisms are connected to the pipe distributor by the liquid inlet pipes, the liquid working substance sprayed from the spraying mechanisms is returned to the outer liquid working substance tank through the return pipes, and is cooled down by means of the spray hydraulic device and the hydraulic working substance cooling equipment, and enters the inner liquid working substance tank of the auxiliary cabinet, wherein the liquid working substance has no phase transition during the spraying process; a first liquid working substance pump is further arranged inside the auxiliary cabinet, and the first liquid working substance pump is in communication with the pipe distributor; the auxiliary cabinet is further arranged with a first liquid working substance filter, and the first liquid working substance filter is arranged in the inner liquid working substance tank and is in communication with a liquid inlet of the first liquid working substance pump; the spraying mechanisms are configured such that the liquid working substance sprayed to the heat source has a shape of mist; the server cabinet has a fully sealed structure. wherein the cabinet comprises an auxiliary cabinet, a server cabinet, liquid inlet pipes, and return pipes; wherein an inner liquid working substance tank, a main pipe and a pipe distributor are arranged inside the auxiliary cabinet, wherein the pipe distributor is in communication with the inner liquid working substance tank by the main pipe, and both the outer liquid working substance tank and the inner liquid working substance tank are loaded with insulative and thermally-conductive liquid working substance; wherein a server and a plurality of spraying mechanisms are arranged inside the server cabinet, and the spraying mechanisms are disposed directly facing a heat source of the server; wherein the spraying mechanisms are connected to the pipe distributor by the liquid inlet pipes, the liquid working substance sprayed from the spraying mechanisms is returned to the outer liquid working substance tank through the return pipes, and is cooled down by means of the spray hydraulic device and the hydraulic working substance cooling equipment, and enters the inner liquid working substance tank of the auxiliary cabinet, wherein the liquid working substance has no phase transition during the spraying process; a first liquid working substance pump is further arranged inside the auxiliary cabinet, and the first liquid working substance pump is in communication with the pipe distributor; the auxiliary cabinet is further arranged with a first liquid working substance filter, and the first liquid working substance filter is arranged in the inner liquid working substance tank and is in communication with a liquid inlet of the first liquid working substance pump; the spraying mechanisms are configured such that the liquid working substance sprayed to the heat source has a shape of mist; the server cabinet has a fully sealed structure.