The optical system is divided into four segments in this study, according to the apochromatic and high-resolution requirements of the machine vision lens, and the initial structure of each segment is optimised independently before being merged to obtain the initial structure of the lens segment. The Buchdahl dispersion vector analysis method is employed to perform targeted replacement of some glass materials, and multiple optimisations are applied to provide an apochromatic machine vision optical system that fulfils the criteria of optical performance. The focal length of the system is 60 mm, the half field of view is 11° and the F-number is 5.45. The image field can match a 1″ large target CMOS camera, and each field of view has a modulation transfer function value of 200 lp/mm. At an aperture of 0.707, the system’s residual chromatic aberration is 0.01665 μm, which is within the system’s chromatic aberration tolerance. The secondary spectrum of the system is 0.08385 μm, indicating that the optical system is apochromatic. The Buchdahl dispersion vector is shown to be effective in the experiments. In the process of grouping design and overall optimisation of the lens system, the analysis method can provide greater convenience for the selection of optical glass and the overall optimisation of the system.