In recent years, with the rapid development of indium gallium arsenide (InGaAs) detectors, shortwave infrared (SWIR) technology has demonstrated unique advantages in fog penetration and night-time detection, leading to widespread applications in night navigation, assisted driving, military reconnaissance, and other fields. The introduction of 1280×1024 pixel InGaAs detectors in China has underscored the growing importance of developing SWIR optical systems with large-area arrays and large relative apertures. To address the demands of night vision imaging in complex environments, this study presents the design of a SWIR optical imaging system based on a 1280×1024 pixel InGaAs detector with a 15 μm pixel pitch. The system enables high-resolution, wide-field imaging and is built upon a classical double Gaussian optical configuration. By employing a carefully selected combination of commonly used visible-light optical materials, the design achieves apochromatic correction across the SWIR band. The resulting optical system offers key advantages, including compact size, large relative aperture, high resolution, and excellent manufacturability.