The present application provides a novel water cooling radiator with a detachable water pump and a built-in fan, which enables outside air to enter a cooling housing from air inlet holes in an upper end of the cooling housing and be discharged from air outlet holes in a lower end of the cooling housing, so that the air discharged from the air outlet holes can dissipate heat from and cool down various electronic components such as MOS tubes and memory chips around the motherboard and CPU, thereby improving the heat dissipation efficiency and prolonging the service life of the motherboard. A pump is connected externally to the radiator, which makes the installation and connection more convenient and the performance better.