The invention relates to a nanometre spraying device and method thereof for realizing a high-load CPU enhanced heat dissipation function, belonging to the field of research of internal combustion engines. The nanometre spraying device comprises a PCB, a CPU, a thin copper plate, a condenser pipe, a spraying cavity, a cooling liquid tank, a filter, cooling liquid, an effect mechanism and a controller; when a CPU thermistor on the PCB monitors that the temperature of the CPU is beyond a limit value, a nozzle is opened; cooling liquid fog droplets are sprayed on the thin copper plate on the surface of the CPU; heat on the surface of the CPU is taken away through film boiling heat exchange and forced-convection heat exchange; after being congealed on the condenser pipe, steam flows down along the wall surface and enters a radiator through a cooling liquid recovery hole, such that steam flows back into the cooling liquid tank; a more effective and energy-saving heat dissipation manner is provided for high-power equipment; the heat conductivity coefficient of the cooling liquid is increased by adding nano-particles into the cooling liquid; therefore, the heat dissipation efficiency of the device is further increased; all the adopted components are micro-equipment; the power consumption is low; but, the heat dissipation effect is high; therefore, a lot of electricity can be saved; and the nanometre spraying device and method disclosed by the invention have an important meaning in the energy-saving and environment-friendly aspects.