To address the decline in binocular ranging accuracy under low-contrast conditions, such as haze and strong background interference, this study integrates computer-based image enhancement techniques and optimizes depth information calculation and image processing methods to achieve high-precision passive binocular ranging in low-contrast environments. First, image enhancement techniques are applied to improve the accuracy of feature point recognition and matching in binocular images, thereby enhancing image quality in low-contrast settings. Next, a 3D display device is introduced in the image reconstruction terminal to optimize depth information calculations, ensuring accurate distance measurement even when image features are severely degraded. Through binocular stereoscopic vision, the automatic fusion and registration of target images are achieved, extending the ranging distance and improving accuracy. Experimental results show that, compared to the 10% ranging error of the traditional Type 58 rangefinder, the binocular stereo vision ranging method proposed in this paper achieves an average relative error (MRE) of less than 2.3% within a range of 500 m to 1 300 m. Additionally, this method demonstrates excellent stability, reliability, and real-time performance in low-contrast environments. The proposed method enables real-time, rapid, passive binocular ranging of moving targets in low-contrast conditions, offering high accuracy and strong anti-interference capabilities, making it suitable for industrial control, driver assistance, and target indication applications.