Cooling device for data centre machine cabinet, machine cabinet, and cooling system

Disclosed are a cooling device for a data centre machine cabinet, a machine cabinet, and a cooling system. A specific embodiment of the cooling device comprises: heat pipes, evaporation ends being arranged on the surface of a heat source of a server in a machine cabinet, and condensation ends being inserted into heat pipe insertion holes of heat exchange pipes in a heat exchanger; and the heat exchanger, arranged on a back plate of the machine cabinet, a liquid-state refrigerant input pipe being arranged at the bottom of the heat exchanger, a gas-state refrigerant output pipe being arranged at the top of the heat exchanger, wherein the heat exchange pipes, in communication longitudinally, are arranged between the liquid-state refrigerant input pipe and the gas-state refrigerant output pipe, and the heat pipe insertion holes are provided on the heat exchange pipes. The embodiment can quickly export heat dissipated from a heat source in a server, thus improving the heat dissipation efficiency of a high heat-dissipation capacity device or a high-density device.