To address the issue of low accuracy in 3D modeling of images captured by unmanned aerial vehicles (UAVs), the authors propose an enhanced 3D reconstruction model for a mountain in Yuanmou by employing an improved Structure from Motion–Multiview Stereo (SFM–MVS) algorithm. In the process of converting 2D into 3D data, the key challenges lie in feature point extraction and matching. The authors introduce an algorithm for optimizing Speeded Up Robust Features (SURF) by combining the SURF descriptor operator with a fast feature point algorithm. The use of the Laplace operator to refine the extraction of weighted feature points along with integration into the robust SURF descriptor simultaneously improves both matching speed and accuracy. This solution mitigates issues related to excessive image data and the low accuracy and efficiency of 3D reconstruction models in UAV applications. Experimental results demonstrate that the proposed method extracts more feature points, increases matching speed, and significantly enhances accuracy compared to both the original SURF and traditional Scale-Invariant Feature Transform algorithms. When compared to the unoptimized SFM–MVS algorithm, the accuracy of the optimized 3D reconstruction using the SURF-based algorithm improves by approximately 44.68%, with a 30% increase in processing speed. Additionally, to evaluate UAV path planning performance on complex terrain, the authors first employ the optimized SURF-based 3D reconstruction method to precisely reconstruct the terrain map of the target area. This method improves both the accuracy and efficiency of 3D terrain reconstruction, providing high-precision data for subsequent path planning algorithm performance testing. Subsequently, three classical path planning algorithms—Ant Colony Optimization, A*, and Rapidly exploring Random Tree—are selected for comparative analysis of UAV path planning capabilities on complex terrain.