The propagation of aberrant flat-topped multi-beam passing through turbulent atmosphere is investigated based on the extended Huygens-Fresnel principle. The analytical expression for the cross-spectral density of this multi-beam propagating through the turbulent atmosphere is obtained. Power In Bucket (PIB), Signal to Noise Ratio (SNR) and Bite Error Rate (BER) are calculated numerically. The effects of the order of the flatness, aberration coefficient, wavelength, correlation length, seperation distance and beam width on these link's parameters are studied and analyzed. The result is shown by some graphs.