Water jet-guided laser technology is an efficient processing technology that offers the advantages of a small heataffected zone and strong depth capability when processing a variety of difficult-to-process materials. However, the surface of the laminar water column can form irregular disturbances due to nozzle damage and other factors, ultimately leading to an uneven distribution of laser light intensity, causing a loss of laser power. In this paper, the relationship between the quality, morphology and coupling alignment errors of the water column on the optical transmission efficiency of water-guided lasers is investigated in depth with ray tracing method. Besides, the water column surface variable-angle prismatic disturbance model is established, considering the characteristics of the real water column to research the impact of the real situation relationship. The results show that the loss of laser energy is more severe as the complexity of the surface morphology of the water column increases. In addition, laser coupling alignment errors are studied. The results show that a circular distribution is formed in the water column when the alignment deviation occurs. Finally, the reasons affecting the laminar flow conditions are analyzed to provide theoretical support for efficient laminar coupled light transmission.