通过理论分析和数值模拟，对聚焦平台光束大气传输的焦移问题进行了研究。聚焦平台光束在湍流大气中传输时，湍流将导致光束的束腰向发射点移动，且湍流越强移动的幅度越大；大气湍流强度相同时，聚焦平台光束发射口径越小，其束腰移动的幅度越大。另外，通过调节发射系统的焦距，使聚焦平台光束的束腰正好位于接收探测器处时，接收探测器上的激光功率密度并非最大，只有当发射系统的焦距等于激光的传输距离时，接收探测器上的激光功率密度才会最大。

Through theoretic analysis and numerical simulation, the focal shift of a focused flat beam propagating in turbulent atmosphere is studied. When a focused flat beam propagates in turbulent atmosphere, the effect of turbulence will induce the focal spot to move toward the transmitter. The turbulence is stronger and the diameter of transmitter is smaller, the measure of focal shift is larger. When adjusting the focus of transmitter and letting the focal spot of beam locate on detector, the laser intensity received by detector is not the strongest. The laser intensity will be the strongest if the focus of transmitter equals to the distance from transmitter to detector.