This study investigates dynamic structural displacements estimation using displacement–strain relationship and measured strain data. Strain signals are obtained from fiber Bragg grating (FBG) sensors that have an excellent multiplexing ability. Vibration experiments were performed with aluminum and acryl beam specimens. The beam structures were subjected to various loading conditions, and deformed shapes were reconstructed by using strain signals. The estimated displacements show good agreements with those measured directly from laser displacement sensors. In present study, it is confirmed structural displacements can be estimated using strain data without displacement measurement.