The invention relates to a method for performing optical fiber channel check without power outage on an intelligent substation. The method comprises the following steps: in a direct sampling loop, accessing a first optical fiber splitter to a current combining unit, separating two optical fibers to connect to a second optical fiber splitter through the flanges, and then accessing to an intelligent protecting device of the intelligent substation, disconnecting any optical fiber between the first optical fiber splitter and the second optical fiber splitter when preforming the optical fiber channel check, accessing two splices of the disconnected optical fiber into an optical channel check device; in a direct tripping loop, accessing the third optical fiber splitter to the intelligent terminal, separating two optical fibers to respectively connect to the fourth optical fiber splitter through the flanges, and then accessing to the an intelligent protecting device of the intelligent substation, disconnecting any optical fiber between the third optical fiber splitter and the fourth optical fiber splitter when preforming the optical fiber channel check, concurrently accessing two splices of the disconnected optical fiber into the optical channel check device. By use of the method disclosed by the invention, the power outage of the primary equipment is unnecessary when performing the optical fiber channel check.