利用高速摄像技术检测脉冲CO2激光诱导液体气穴通道形成、发展和坍塌的动态过程，考察不同聚焦辐照条件对气穴效应的影响。实验获得了气穴通道脉动过程的序列图像，得到了表征气穴通道特性的参数（如最大穿透深度等）。实验结果表明，不同聚焦条件对气穴通道的动力学过程有显著影响。正离焦及焦点位置条件下，气穴通道在最大纵深时，整体形态类似于漏斗状，而负离焦条件下，则呈U 形。研究结果对激光医疗、激光水下加工、能源等领域的研究具有一定的参考价值。

The dynamic process of generation, propagation and collapse of vapor channel induced by pulsed CO2 laser is monitored by a high speed camera. The influence of different defocus conditions on vapor channel is investigated. Sequence images of vapor channel process are captured, and coefficients that characterize vapor channel such as maximum depth are acquired. The results show that different defocus conditions have significant impact on kinetic process of vapor channel. Under pre-focus and focus plane conditions, the shape is similar to a funnel as the vapor channel propagates to the maximum depth, however, under the post-focus condition, the shape is similar to U. The experiment results provide reference for laser medicine, underwater laser processing and energy fields.