Abstract-Vibration test on hull structures with large size needs numerous amounts of sensors, which means too much work. However, notable error would come from reducing the number of sensors. An approach is proposed to reconstruct the complete structural vibration, which chooses the locations and the number of sensors optimally based on the condition number of structural modal matrix. This iterative progress eliminates the sensor location that contributes the most significantly to the condition number of modal matrix in each cycle. The influence of the location number eliminated in each cycle is analyzed and emulated. An experiment validates the precise of this approach; the error is only 3.0 dB. The distributions over the surface of structure are also consistent between reconstructive and measuring data.