利用数值模拟方法，采用桶中功率为86.5%定义的环围功率束宽作为光束扩展的评价参数，研究了环状光束在大气湍流中沿斜程路径传输的光束扩展。研究结果表明，自由空间中遮拦比越大，远场光强旁瓣越明显。大气湍流造成光强旁瓣消失，且远场光强分布并不是高斯分布。光束扩展随着遮拦比和天顶角的增大而增大，大气湍流对光束扩展的影响也随天顶角的增大而增大。当遮拦比较大或较小时，湍流对光束扩展影响随遮拦比的增大而减小；当遮拦比中等大小时，湍流对光束扩展的影响几乎不随遮拦比而变化。与已有研究结果比较发现，按照桶中功率不同百分比定义的环状光束环围功率束宽受大气湍流影响规律是不同的，研究结果对实际应用具有意义。

Taking the encircled-power width defined by the power of 86.5% in the bucket as the characteristic parameter, the spreading of annular beams propagating through atmospheric turbulence along a slanted path is studied by using the numerical simulation method. It is shown that in free space, the lobe of the far-field intensity distribution appears with the obscure ratio increasing. The lobe disappears due to the turbulence, and the far-field intensity distribution is not a Gaussian profile. The beam spreading increases as the obscure ratio and the zenith angle increase, and the influence of turbulence on the beam spreading increases when the zenith angle increases. However, when the obscure ratio is large or small, the influence of turbulence on the beam spreading decreases as the obscure ratio increases; when the obscure ratio is middling, the influence of turbulence on the beam spreading is nearly unchanged versus the obscure ratio. Compared with previous work, it is found that the law of the influence of turbulence on the spreading of annular beams is different if the percentage of the power in the bucket is different. The results are useful for practical applications.