The invention relates to a device for regulating the precompresssion amount of a closing spring. The device comprises at least two supporting columns fixed on a spring casing, wherein the supporting columns extend in the compression direction of the spring and are sleeved with a push plate moving in the axial direction of the supporting columns in a guide mode, at least two top rods are arranged on the push plate, and containing space is reserved among the top rods and used for containing locking nuts arranged on a closing pull rod and used for locking a compressed spring plate. Each supporting column is provided with a driving mechanism and a locking structure, wherein the driving mechanism is used for driving the push plate to move in the axial direction of the supporting columns to a direction compressing the closing spring, and the locking structure is used for preventing the push plate from moving to the extension direction of the closing spring under the action of elastic force of the closing spring after the closing spring moves in place. By means of the device, the compression amount of the closing spring can be regulated directly without removing an operating mechanism, the operation is convenient, and work efficiency is increased. In addition, the device is simple in structure, convenient to carry and capable of overhauling and debugging the closing spring in an operation environment on site.