The invention relates to the technical field of static loading test displacement observation, in particular to a pile foundation self-balanced static loading test displacement observer which comprises two sections of acoustic wave detecting pipes, a positioning pipe, a displacement wire and an automatic hook, wherein the diameter of the positioning pipe is greater than that of each acoustic wave detecting pipe; the two sections of acoustic wave detecting pipes are concentrically arranged two ports of the positioning pipe correspondingly; a cover plate is welded between the ports of the positioning pipe and the corresponding ports of the acoustic wave detecting pipes to form an enclosed structure; the automatic hook is arranged in the positioning pipe in a penetrating manner and connected with the positioning pipe in a matched manner; and the lower end of the displacement wire is fixedly connected with the automatic hook. The pile foundation self-balanced static loading test displacement observer provided by the invention is reasonable in structure; by virtue of the acoustic wave detecting pipes which are utilized for a super-long foundation pile and pre-buried by adopting an acoustic wave transmission method, the mounting program for a displacement test can be simplified, the progress in the trial assembly of a safety-protection steel reinforcement cage during pile formation can be sped up, and then the construction efficiency can be improved; and besides, the displacement wire and the automatic hook can be recycled, thereby reducing the test cost.