The effect of turbulent atmosphere on the propagation of coherently combined laser beam is studied. Propagation of coherently combined laser beam in turbulent atmosphere is numerically calculated by using generalized Huygens-Fresnel principle. The statistical characteristics, i.e. power in the bucket (PIB) curve and fractional power curve are calculated. It is revealed that the propagation of coherently combined beam suffers less in weak turbulence, and the irradiance distribution and PIB curve in the receiving plane are the same as its counterparts in free space. However, the beam spot will spread faster as the effect of turbulence gets stronger, and the energy centrality reduces evidently. The spectral degree of coherence of laser beam after propagation in the turbulent atmosphere is calculated. It is revealed that degrading in beam coherence causes the declining of coherent combinination. The way for eliminating the effect of turbulent atmosphere is discussed.