Abstract: Medium-voltage distribution networks in high-altitude farming and pastoral areas are constrained by long supply radius, dispersed loads, severe climate, and ecological restrictions. Taking Yushu, Qinghai as a case study, this paper establishes a five-type supply-form system for different scenarios and develops an integrated evaluation framework covering structural adaptability, reliability, economy, and ecological constraints. The entropy-weighted TOPSIS method is used for ranking candidate schemes, and a life-cycle cost model is adopted to identify the economic boundary among alternatives. Results show that in long-radial feeders with low load density, difficult fault restoration, or strong ecological constraints, end-storage support and PV-storage microgrids can effectively shorten the equivalent supply chain, improve terminal voltage, and reduce comprehensive cost. For the typical Yushu case, when the supply radius is about 18-22 km under low load density and high restoration cost conditions, the storage-supported mode begins to outperform conventional line extension. The study emphasizes scenario adaptability and the systematic nature of the evaluation framework, and can provide a reference for planning medium-voltage distribution networks in similar alpine regions.