This study addresses the contrasting issues of vulnerability and sustainable development within tourism economies. Recognizing that heightened vulnerability can lead to tourism crises and disrupt sustainability, I delve into the vulnerabilities in the sensitive tourism sector, considering both internal instabilities and external disruptions. My examination is based on two lake regions, Erhai Lake in China and Lake Balaton in Hungary, and I adopt various analytical methods, including set pair analysis, entropy method, and comparative case study. The dissertation begins by discussing the background, significance, and existing research on vulnerability. This lays the groundwork for an assessment of the balance of industrial structure in both regions, thereby providing an objective view of the tourism landscape. The study then explores the driving factors of vulnerability within the internal tourism economy system and the external regional composite system. Through the lenses of sensitivity and resilience, an evaluation index for tourism economy vulnerability is established. Drawing on this evaluative index, the dissertation studies Erhai Lake and Lake Balaton, using a decade's worth of data to assess their tourism economy vulnerabilities. This process allows for an examination of the temporal and spatial variations in these vulnerabilities and the identification of the key hurdles in reducing them. The study concludes by suggesting sustainable development strategies for each region based on the principles of sustainable tourism. The strategies include acknowledging and addressing vulnerability issues, improving the tourism industry system, responsibly developing tourism resources, and ameliorating the tourism development environment. The research finds that Erhai Lake region's fast-paced growth calls for economic diversification and enhancement of export capabilities. On the contrary, Lake Balaton region should focus on further industrial diversification and the stabilization of its economic and consumption growth. Both regions can benefit from sharing experiences and strategies. In essence, sustainable development in these regions hinges on striking a balance between resources, population, environment, and cultural preservation, which will bolster their resilience and ensure equitable sharing of growth benefits.