Two-way direct investment is crucial to the realization of high-quality regional economic development and the upgrading of value chains. With the introduction of the "Belt and Road" initiative and the deepening of opening up, two-way direct investment continues to be active, which not only brings huge economic benefits to enterprises, but also generates significant spillover effects in terms of technology import and efficiency enhancement, and effectively empowers the high-quality construction of new western land-sea corridor. In the context of high-quality development, it emphasizes economical, efficient, convenient, environmental-friendly and safe high-quality construction of the corridor. And it has formed new competitive advantages in rearrangement and integration of logistics channels at home and abroad, new infrastructure empowerment and trade facilitation. Thus, it is of great theoretical and practical significance to explore the internal mechanism, value enhancement, short board analysis and realization path of the high-quality development of two-way direct investment in new western land-sea corridor oriented by the new competitive advantages. Based on the panel data of two-way direct investment generated from east China, central China and 10 provinces or cities in the corridor from 2010 to 2021, this study investigates the high-quality development of two-way direct investment in the corridor and its spillover effects in terms of quantity and quality. Firstly, by analyzing the new competitive advantages of international trade, the key factors for improving the quality and quantity of two-way direct investment in the corridor are identified. Secondly, this paper analyzes the role of the high-quality development of two-way investment in improving the new competitive advantage of the corridor from three aspects of logistics efficiency, trade facilitation level and new infrastructure construction. Then, this paper deeply analyzes the spatial and temporal evolution characteristics and regional differences of two-way direct investment in terms of quantity and quality, and shows the shortcomings of two-way direct investment in 10 provinces and cities in the corridor. Finally, based on the results of the study, targeted countermeasures are proposed for the high-quality development of two-way investment in the corridor. The study shows that there are shortcomings in both quantity and quality of two-way direct investment in the 10 provinces and cities of the corridor. Compared with the eastern and central China, its quantitative shortcomings are mainly reflected in the smaller and slower increase in the total amount of foreign direct investment, the slow growth rate of outward direct investment and the larger gap with the eastern region; the qualitative shortcomings are mainly reflected in the prominent negative environmental effects of foreign direct investment, the lack of obvious industrial structure upgrading assistance, and the lack of significant technological spillover effects, as well as the low level of outward direct investment, and the lack of government support and guidance. According to the conclusion of this paper, there are corresponding policy suggestions: trade facilitation, new infrastructure construction, full play of the regional advantages of core logistics hubs, cultivation of core competitiveness of enterprises’ foreign direct investment, and scale effect efficient in the aggregation and flow of factors.