The invention discloses an external heat-dissipating computer host case, which includes a box body, a fixing plate is arranged in the box, and the upper surface of the fixing plate is fixedly connected with the lower surface of a first driving device through a fixing rod. The left side of the first driving device is fixedly connected to the right end of the first connecting rod, the lower surface of the first connecting rod is fixedly connected to the upper surface of the extruding block through the second connecting rod, and the lower surface of the extruding block It is overlapped with the upper surface of the extruding plate, and the lower surface of the extruding plate is fixedly connected with the upper surface of the second driving device through a slide bar. The external heat dissipation computer mainframe chassis, through the first motor, turntable, first connecting rod, second connecting rod, extruding block, extruding plate, sliding rod, sliding sleeve, telescopic rod, spring, second motor and fan The mutual cooperation between the leaves achieves the purpose of cooling the computer mainframe, thereby ensuring the service life of the mainframe and facilitating the work of the staff.