Abstract: With the wide applications of machine vision technology in the fields of advanced manufacturing system, robot system, intelligent monitoring and aerospace military industry, the miniaturization and dexterization of bionic vision system has become one of the important research directions. Aiming at the shortcomings of traditional machine vision system, such as complex zoom structure, easy wear and low life, a bionic optical system with liquid lens was designed and built on the basis of the principle and imaging characteristics of liquid lens. The main technical parameters of the system are as follows: the focal length range is 18.5 mm~22.5 mm, the lens zoom ratio is 1.22, and the field angle is 38 °×24 °. The design results accord with each index, and the image quality can meet the requirements at different focal lengths, which can realize real-time focusing. The size of the whole optical system is 36 mm×55 mm×30 mm, which has a compact structure and strong practicability.