光斑扩展是光束在大气湍流中传输时的一个重要效应。利用光束动态变化测试系统在烟台地区近海面进行了准直高斯光束传输实验，在测量光斑扩展、温度、相对湿度和大气折射率结构常数等数据的基础上，分析了近海面准直高斯光束光斑扩展的变化特征。分别选择不同距离的链路和不同时间段进行实验，分析光斑扩展的变化情况。研究结果表明：近海面大气湍流中的光斑扩展半径与大气折射率结构常数相关性在晴朗时比风浪较大时要好。在风浪较大时，光斑扩展半径与大气折射率结构常数相关性较差，但在一定时刻与温度和相对湿度相关性较好；在链路距离相同的条件下，夜间光斑扩展半径明显小于昼间，且夜间光斑起伏幅度也小于昼间。

Beam spreading is an important effect when a beam propagates in atmospheric turbulence. The collimated Gaussian beam spreading experiments are carried out with beam dynamic change test system under the sea surface environment in Yantai region, and the beam spreading characteristics are analyzed based on data including beam spreading, temperature, relative humidity and atmospheric refractive index structure parameter in different distances and different time periods experiments. Results show that the correlation between beam spreading and refractive index structure parameter is better in sunny weather than in stormy waves weather. But in stormy waves weather the correlation between beam spreading and temperature and relative humidity is good at certain time. In the condition of the same link distance, the beam spreading is obviously smaller at night than in day, and the amplitude fluctuation of beam spreading has the same results.