A CPU heat dissipating unit for assembly into a 1U industrial computer, wherein, used to improve the effect of dissipating heat, mainly consisting of a cover unit, a tunnel unit and a heat dissipating fin. The cover unit is assembled to an upper side of a power supply unit, forming a ventilation channel between them. A heat dissipating unit is assembled on an upper side of the CPU and stored suitably into one side of the tunnel unit, while a cooling fan is assembled on the other side, thus providing quick dissipation of heat produced by the CPU.