Abstract: The invention relates to precision measurement technology, specifically a high-sensitivity three-dimensional topography recovery method using dual-channel differentiation. Enhancing a traditional microscopic imaging system, a beam splitter is added between the objective lens and tube lens. This creates an additional light path equipped with a tube lens and camera identical to the original but with a slightly different distance to the camera. During axial scanning of the object, focusing evaluation function curves for each pixel are calculated from images captured by both cameras. The curves from the two cameras show more significant changes near the optimal focusing depth, improving system sensitivity. This method enhances sensitivity by hardware-fixed differentiation of the focusing evaluation function, while maintaining high scanning efficiency and flexible configuration.