The invention relates to a method and device for observing settlement of a huge building foundation. The device comprises an embedded part, a conducting mechanism and a signal indicating mechanism, wherein the conducting mechanism comprises a telescopic rotating rod, a rotating shaft, a vertically arranged protective tube and a rigid connecting rod which is arranged in the protective tube, one end of the rigid connecting rod is fixedly connected to the embedded part embedded in a foundation and the other end is hinged to one end of the telescopic rotating rod, the telescopic rotating rod is vertical to the rotating haft and the other end of the telescopic rotating rod is fixed on the rotating shaft, the signal indicating mechanism comprises a laser indicator arranged on the radial direction of the rotating shaft and a corresponding projector screen; and a shaft seat of the conducting mechanism and the signal indicating mechanism are correspondingly arranged on a heavy load pile foundation bearing platform framework, deformation generated by the embedded part with the settlement of a pile foundation is transferred to the signal indicating mechanism through the conducting mechanism,and the settlement is displayed by the signal indicating mechanism or is calculated or reckoned by a display signal of the signal indicating mechanism. The invention has the advantages of vision of display, simplicity for operation and maintenance, reliable performance and capability of immediately and accurately detecting the settlement of the building by people.