The invention discloses a method for replacing a height-adjustable support. The concrete construction technology of the method comprises the following steps of: mounting a temporary support at a position close to the side surface of the support, and adjusting the temporary support to be tightly attached and fixed with an upper structure and a lower structure; lowering the height of the support, and unloading the load of the support; disassembling the support to be replaced, and installing a new support; and adjusting the support to the initial position, and detaching the temporary support. A synchronous jacking technology can be replaced, rapid replacement of a
single support in the operation period is achieved, a bridge does not need to be jacked, the technical difficulty is small, the danger coefficient is low, the occupied area is small, the coordination
workload is small, medium-broken bridge operation is not needed, and the cost is low.