The invention discloses a settlement control device and method for jacking a pipe to underneath pass the existing operating railway for construction. A settlement measuring unit is arranged on a sleeper, a laser pen positions on a screen ruler, and when the sleeper sinks or bulges, the screen ruler at the corresponding position can ascend or descend, so that the irradiation position of the laser pen is changed. The screen ruler sends the change data to a control unit, and the deformation of the sleeper is collected. A settlement control unit is arranged in the soil body below the sleeper, whenthe sleeper sinks or bulges, the control unit collects the settlement or bulge data, and determines the screen ruler corresponding to the deformation, and controls an air bag at the corresponding position to be inflated or deflated, thereby achieving the purpose of straightening a packaging rail. According to the method, on the construction condition of jacking the pipe to underneath pass an existing railway, the straightness of the railway is guaranteed, and the situation that the ground surface sinks or bulges during construction, and consequently the vehicles on the railway are affected, is avoided.