The invention discloses an adjusting mechanism for rotor centration by utilizing a piezoelectric crystal, comprising a bearing-rotor system installed in a bearing block; the bearing block is installed in a shell through a plurality of groups of piezoelectric execution units distributed along an axial direction of the bearing block; each group of piezoelectric execution units comprises a pluralityof piezoelectric crystal actuators distributed along the circumferential direction of the bearing block; each piezoelectric crystal actuator comprises an end cap, a heat-shrinkable fin and a piezoelectric crystal, a circular truncated cone head of the piezoelectric crystal is matched with a corresponding conical hole in the bearing block, and the other end of the piezoelectric crystal is providedwith the heat-shrinkable fin embedded into the end cap connected with the shell through screw threads; and the deformation of the piezoelectric crystal is realized through changing the current in thepiezoelectric crystal actuators by utilizing an inverse piezoelectric effect of the piezoelectric crystal so that he position of the bearing block is changed; and the rotor position is changed through the bearing-rotor system, so that the aim for rotor centration is achieved. The invention has the advantages of simplicity and rapidness in centration and high precision.