Double-telecentric lenses present the advantages of low distortion and large depth of field. Therefore, they are widely applied in the online detection of the machine vision industry. This study presents an optical design for a three-magnification double-telecentric system based on machine vision. The telecentric system is divided into objective and eyepiece parts by setting a refractive prism as the boundary. Different optical magnification in the original system could be realized by replacing the eyepiece, which ensures the applicability of the telecentric systems in outline and detail. In this study, we designed a three-magnification double-telecentric system with high definition and low distortion using the optics design software. In the proposed system, the working distance is 110 mm and the object fields of view are 100 mm and 25 mm. The optical magnifications are -0.11, -0.24, and -0.44. The system achieves low distortion (<0.05% in each field of view) and high resolution (>0.3 at 145 lp/mm). Additionally, it meets other design requirements. Furthermore, the relationship between fields of view and optical design is investigated.