A gradient-index lens with a diameter of 1.8 mm, a cylindrical lens with a diameter of 2.5 mm and a volume Bragg grating are designed and fabricated as an optical system for a commercial blue single-tube semiconductor laser with a fast axis full width at half maxima of 23°. The experimental results show that this scheme can achieve a beam width of 0.48 mm at a distance of 5.5 m from the system, and the beam width is less than 0.60 mm in 5.5±0.5 m nearly, which can provide a new solution for the selection of the measurement scheme of line structured light.