The accuracy of mineral reserves assessment directly determined the investment decision and mining plan of mining enterprises, and the accuracy of geological survey drawing was the core spatial data basis of reserves assessment model. This paper systematically discussed the influence mechanism of geological survey drawing accuracy on mineral reserves evaluation, and constructed the influence model of plane coordinate and elevation error on volume calculation based on the law of error propagation. The research showed that in the traditional geological measurement mode, the elevation interpolation error and boundary delineation deviation would cause significant distortion of reserves estimation. Aiming at this problem, a measurement optimization path based on multi-source three-dimensional laser scanning and UAV airborne LiDAR fusion technology was proposed, and a three-dimensional spatial Kriging interpolation algorithm was introduced to optimize geological modeling. Based on the engineering practice of Shanxi Xinjing Coal Mining Co., Ltd., the comparative analysis showed that after adopting the optimized path, the density of the measured point cloud was increased to 200 pts/m2, and the root mean square error of the elevation was reduced to less than 0.05 m. Compared with the traditional measurement method, the three-dimensional high-precision measurement corrected the volume calculation deviation caused by the fluctuation of the coal seam floor, and the accuracy of reserve evaluation increased by 2.34 %.