In the atmosphere laser communication, scintillation caused by atmospheric turbulence could seriously affect the performance of communication system and increase bit error rate. Multi-beam transmission is an effective method to overcome this effect. We analyze the intensity probability distribution when transmitting with different numbers of beams and analyze the intensity probability distribution with different aperture diameters when transmitting multi-beam. The results show that when the transmitting beam and the aperture diameter increase, intensity probability distribution more likely tend to normal distribution and the mean intensity probability density also increases. This article also analyzes the relationship between the normalized correlation coefficient of multi-beam transmission and the intensity variance. Besides, the bit error rate of multi-beam transmission in different turbulent environment is analyzed. Analysis results show that multi-beam transmission system can improve the intensity fluctuation on receiving surface well and reduce bit error rate