The present invention discloses a three-segmental silicon oil fan clutch which includes a housing (5), a oil storage cap (12), a temperature-sensing ring (11), a front cover (7), a drive shaft (2), and an active board (4), wherein the oil storage cap (12) is disposed on the rear end of the front cover (7) and forms a oil storage cavity with the front cover (7); the active board (4) forms a engaged cavity with the front cover (7) and the housing (5); a valve sheet (8) is set inside the oil storage cavity; the temperature-sensing ring (11) is set on the external surface of the front cover (7) and connected with the valve sheet (8), characterized in that the inner wall of the front cover (7) extends in transverse and has a separating part (1e) that separates the oil storage cavity into a main oil storage cavity (2a) and a secondary oil storage cavity (3a); the oil outlet hole includes a main oil outlet hole (3b) a first culvert opening (1b) and a second culvert opening (2b) that close tothe first culvert opening (1b). Compared with prior art, the present invention is provided with features like more reasonable and simple integral structure, components production and installation cost reduced effectively, meanwhile energy consumption low, and noise small.