Long approach viaducts of major river crossings are characterized by extensive lengths, tall piers, substantial longitudinal variation in pier height, and large capital investment. Their structural selection directly affects structural behavior, construction safety, project economics, and durability in service. In this study, the approach viaducts of four Yangtze River bridges in Jiangsu Province—the Husutong, Wufengshan, Changtai, and Zhangjinggao bridges—were examined. A systematic comparison was conducted in terms of their mechanical behavior, spanning capability, economics, aesthetics, adaptability to construction conditions, and ease of operation and maintenance. A tiered span-selection framework for zones with low, medium-height, and tall piers was developed, and preferred structural forms for land-based approach viaducts were identified. A quantitative evaluation model based on the analytic hierarchy process was also established. These findings provide reference data for scheme comparison and design optimization in similar projects.