For the purpose of study on diameter, velocity and concentration of air bubbles in water, an optical system of illumination and 3D photography based on high-speed imaging charge-coupled device is proposed. Based on Galileo structure with three cylindrical lens and semiconductor laser of wavelength 532 nm, a light sheet with thickness of 1.5 mm and width of 44 mm is designed. Three groups of imaging lens with magnification of 0.4×， 1× and 2.5×, having a uniform conjugate distance of 530 mm are designed. Each group relayed by collimated light includes frontal lens and focusing lens. A simple and reliable structure of 2D high-speed photography for the area of 60 mm×40 mm and 1D scan with length of 5 mm along the optical axis, is achieved by moving light sheet and frontal lens synchronously. The imaging quality of the optical system with magnification of 0.4×, 1× and 2.5× is evaluated, it shows that the modulation transfer function of 0.707ω has reached 0.58, 0.55 and 0.38 respectively at the spatial frequency of 50 lp/mm, as well as the diameter resolution of air bubbles in water has been from 10 μm to 450 μm.