Abstract: Three-dimensional design using high-performance computer 3D modeling software to design the overall design of power transmission and transformation engineering, output design results in various ways such as 3D visual model and traditional 2D design drawings, meet the output requirements of various engineering products, and respond to subsequent power grid construction. The need for operational management is conducive to improving the intrinsic safety level of the grid project throughout its life cycle and is an important means of building a smart grid. Based on the 220 kV transmission line project of a hydropower plant, the achievable role of 3D design in the survey and design of overhead transmission lines is analyzed. The crossing distances are quantified in the 3D model. By comparing the differences between 2D and 3D designs in the feasibility study and preliminary design stages in terms of path optimization, quantity statistics, and cost control, the specific optimization effects of 3D technology to achieve the goal of optimizing the path and project cost is summarized.