The purpose of the study on experiment technology of laser induced fluorescence in water tunnel is to provide a practical, intuitive, and effective method for flow visualization on separation and vortex structure. Rhodamine B was selected as the stain and fluorescence agent which matched the optical parameter and the characteristics of green laser sheet with 532 nm wavelength in 1 m×1 m water tunnel. The study focused on the key technical problems such as the constitution and preparation method of stain and fluorescent agent, the selection of the optimum intensity of continuous laser, the matching relationship between flow velocity and the pore pressure of dyeing line and the matching relationship between camera field of view and the flow structure in the contrast of fine adjustment. The experiments were carried out to investigate the flow field around a cylinder, the wing of a transport plane model and the cargo door of a transport plane model together with the wake by means of the dedicated laser induced fluorescence experiment technology. The typical experiment results verify that the dedicated laser induced fluorescence technique is suitable for flow visualization on flow separation and vortex structure including boundary layer, spatial separation and wake field which is a promising method worthy of popularization and application.