The global widebody aircraft market is gradually recovering from the COVID-19 and shows a high degree of consistency with 2019. In 2023, the average route distance of global widebody aircraft was 4700 km, significantly shorter than their design range, indicating a limited demand for ultra-long-haul routes. This paper proposes a comprehensive analytical method for selecting the design range of widebody aircraft by integrating market characteristics analysis and operational costs analysis. By analyzing the operational routes characteristics in major global regions and leveraging aircraft performance data alongside the Direct Operating Cost (DOC) method based on the European Airlines Association (AEA) model, the study investigates the impact of reduced design range on aircraft weight, fuel consumption, and operating cost for typical flight segment. The findings aim to provide reference for the preliminary design of widebody aircraft.