The invention discloses an old grid frame hoisting device for capacity expansion of a spent nuclear fuel pool. The device comprises grabbing assembles, a hoisting cross beam and a driving device, wherein the grabbing assemblies are used for being matched with hoisting holes of a bottom plate of an old grid frame, the hoisting cross beam is used for allowing the grabbing assemblies to be installed,and the driving device is used for driving the hoisting cross beam to move; and each grabbing assembly comprises a hoisting rod, a grabbing mounting plate, at least one grabbing mechanism and a grabbing driving mechanism, wherein the hoisting rod is fixedly connected to the hoisting cross beam and is of a hollow shape, the grabbing mounting plate is arranged at one end, far away from the hoistingcross beam, of the hoisting rod, the grabbing mechanisms are arranged on the grabbing mounting plate, and the grabbing driving mechanism is arranged inside the hoisting rod and is used for driving the grabbing mechanisms to complete the grabbing action. According to the device, the lifting rods in the grabbing assemblies extend into a grating, the grabbing mechanisms are each in a loosening state, and when the grabbing mechanisms penetrate through the hoisting holes, the grabbing mechanisms clamp the bottom of the old grid frame; and then the grabbing assemblies with the old grid frame movesupwards to take the old grid frame away from the spent nuclear fuel pool, and therefore the old grid frame can be hoisted out from the spent nuclear fuel pool in the dismounting process of the old grid frame.