The vibration of the string is a series of different frequency and different amplitude and phase of harmonic vibration superposition. These different frequencies are including fundamental frequency, double or triple frequency, and more integer time’s frequency. It is composed of string segment of vibration. The piano sound is spread by the string vibration, through the string to the soundboard that is by the soundboard to air, and then is introduced to the process of the human ear. String vibration is sound energy generated link, its energy is the key to the size of the sound vibration energy; therefore, the sound propagation attenuation problem in the first part is crucial, how to improve the strings attenuation becomes a key problem to be solved. This article aim is that the application of the string vibration theory in the piano strings sound reconstruction and its implementation are discussed.