The invention discloses a portable patrol key case of a transformer substation. The key case comprises a case body formed by connecting a front case body and a rear case body, wherein the peripheries of the front case body and the rear case body are provided with zippers; the rear case body is internally provided with inner interlayers, snap-fasteners are arranged on the inner interlayers, and each inner interlayer is provided with five key hanging mechanisms; each key hanging mechanism comprises a fixed seat, two insertion handles are arranged on the fixed seat, and each insertion handle is provided with a boss through hole and a groove; a spring piece is also arranged on each insertion handle, and a limit boss is arranged on each spring piece; each fixed seat is provided with a connecting seat, the connecting seat is provided with two slots, and the side wall of each slot is provided with a side hole; each connecting seat is internally provided with an inner cavity and two through holes; the lower end of each connecting seat is provided with a key piece slot, the key piece slot is internally provided with a key piece, and a key hole is arranged on the key piece; each inner cavity is internally provided with a connecting plate, and two extruding blocks are arranged on the connecting plate; and a connecting rod is arranged on each connecting plate, one end of the connecting rod is penetrated into the key slot to be fixedly connected with the key piece, and the periphery of the key piece is provided with a second spring.