Abstract: In order to analyze the effect of aberration of amplitude and phase of laser beam on centroid position of focal spot, based on the Fraunhofer formula for light wave scaler diffraction theory, according to the definition of first order moment centroid position, the general expression of focal spot centroid position directly depending on the complex amplitude of near field is derived. The centroid position of the focal spot diretly depending on intensity distribution and phase slope distribution of near field is derived, and its physical meaning is described. The excursion of centroid position of focal spot may be easily acquired with the centroid position expression of focal spot. At last the laser beam with simple aberration, such as no phase aberration and low order Zernike phase aberrati