Based on the extended Huygens-Fresnel principle, the properties of a beam array with random phase distributions propagation through a turbulence atmosphere in a slant path are analytically investigated. Influences of turbulence intensity, duty ratio, transmission height and the phase difference between the beams on the average intensity of the beam array are researched. The results show that turbulence can cause the decrease of the peak and the spreading of beam; at the same time, the smaller the duty ratio, the smaller peak intensity , the combination effect is even worse; with the random phase difference between the beams increasing, the main peak intensity decreases fast and the far-field coherent combining irradiance distribution gradually evolves into the pattern of the single Gauss beam distribution model. The results for a slant path are compared with those for a horizontal path, and as a result, the influence of the atmospheric turbulence to the beam spreading along the slant path is much smaller than that along the horizontal path. The mathematical model and calculation result can offer a reference for choosing and evaluating different combining schemes.