Abstract: Base on the accurate expression of light intensity on the cross section and Rayleigh-Sommerfeld diffraction integrals, the characteristics of axial light intensity of cosh-Gaussian beams diffracted by a small aperture were analyzed and discussed by numerical calculation, and the influences of decentered parameter , the radius of small aperture a and the parameter w0/ on the axial light intensity of cosh-Gaussian beams were also discussed in detail. Results show that the axial light intensity of cosh-Gaussian beams depends not only on the decentered parameter , the radius of small aperture a and parameter w0/, but also on the transmission distance.