Abstract: This article introduces a high-magnification electronic endoscope system, which employs a continuous zoom optical design, enabling high-magnification imaging at the cellular level. By selecting an appropriate initial retrofocus structure, the optimized modulation transfer function (MTF) curve of the zoom objective lens approaches the diffraction limit. In addition, the tip and operation parts of the system incorporate modular gas-tight sealing and multiple layers of protective structures. The design incorporates efficient sealing materials and precise packaging techniques to ensure the system's sealing performance. The experimental results indicate that under conventional imaging, its resolution is equivalent to 39.37 μm in object space and the field of view angle is larger than 140 degree. At the magnified imaging, its resolution is equivalent to 2.78 μm in object space and the observed actual field of view is greater than 800 μm×700 μm. By using the endoscope in conjunction with a 26-inch display monitor, it can achieve 500X optical magnification, enabling the observation of features at the cellular level. Currently, this product has successfully achieved quantified production and undergone multiple animal tests, demonstrating its wide range of potential applications and significant clinical value.