Due to the abundant phenomena of the laser distortion and the physical mechanism of its formation,the research of distortion laser transmission characteristics has become an important optical topic.Therefore,in this paper,by applying the ci rcular aperture diffraction of the laser,and adopting the method of fitting the phase distortion element with the Zernike polynomial function,the beam distortio n of the laser with Gaussian distribution during the circular aperture diffracti on has been discussed.For further study,the effects of the wavelength,the propag ation distance,and order of the function on beam distortion have been analyzed.The results have shown that,under the influence of distortion,d ue to the effect of the astigmatic distortion factor,the beam degrades symmetrically,which leads to splitting,th e position of the central beam intensity is shifted,causing the astigmatism and defocusing distortion.The q value in the Zernike polynomial function significantly affects the amount of beam splitting during distortion,a s the laser wavelength increases, the distortion effect increases as well,and astigmatism and defocusing become m ore obvious.