Abstract: To address the issues of insufficient simulation accuracy and low efficiency in optimizing the layout scheme in the design of photovoltaic power stations in complex terrains, an integrated photovoltaic system design platform was developed. The platform adopts a B/S architecture and integrates terrain analysis, iterative layout, and refined power generation simulation engines. In terms of methods, a terrain model is constructed based on Delaunay triangulation, and automatic iterative layout is supported for multiple parameter combinations such as component model, tilt angle, and azimuth angle; the ray tracing algorithm is used to simulate shading at the cell level, combined with the single diode five-parameter model and inverter efficiency curve, to complete the full-process simulation from irradiation to AC output step by step. Experimental results show that under a scale of 891 schemes, the total computing time of the platform is 78 minutes, which is lower than that of the comparison method. The Pareto front generated by the platform indicates that the levelized cost of electricity can reach as low as 0.335 yuan/kWh. This platform provides an efficient tool and data support for the refined design and economic evaluation of mountain photovoltaic projects.