The planning and construction of the "New Western Land-Sea Corridor" is another initiative of China to promote the two-way full opening of land-sea and regional coordinated development under the "the Silk Road Economic Belt and the 21st-Century Maritime Silk Road" initiative. "Promoting the integrated development of the corridor and regional economy" and "Strengthening the opening of the corridor and international cooperation" are the strategic directions for the development of the "New Western Land-Sea Corridor". In general, organically combining the two theoretical categories of domestic economic geography and international economic and trade relations, based on the analysis of domestic provinces and international competition and complementary relations, this paper explores the domestic and foreign economic and trade foundations for the construction of the "New Western Land-Sea Corridor", and puts forward the development paths of the "New Western Land-Sea Corridor" from the perspective of the economic development model of the open corridor. First of all, based on the point-axis theory, international trade theories and the new economic geography, this paper constructs the theoretical framework of the open corridor economic development model, it indicates that the theoretical essence of the "New Western Land-sea Corridor" is to internally form the western open development convergence axis, externally promote China-ASEAN regional integration and even link up the "Belt and Road". Secondly, from the theoretical perspective of the open corridor economic development model, based on the domestic provincial import and export data from 1987 to 2018, it analyzes the temporal and spatial evolution characteristics of the opening level of covered area of the "New Western Land-Sea Corridor", and it applies the gravity model to calculate the strength of regional economic ties among covered area of the "New Western Land-Sea Corridor", the conclusion shows that from the perspective of the provincial and regional pattern of the western open economy, the overall opening-up level of the southwestern region is in a dominant position, and the economic ties among the southwestern provinces are closer. The "point-axis" spatial development form based on the "Southbound Corridor" and "New Land-sea Corridor" is becoming more and more mature. The opening-up level of the northwestern region is relatively lower, and the economic ties among northwest provinces and between the northwest and the southwest are weaker, which is the potential direction for the extension and expansion of "point-axis" spatial form. Thirdly, based on the international scale, with calculating of the four indicators and relationship network description of trade competition index, trade complementarity index, industrial comparative advantage index and industrial complementarity index of China-ASEAN in 2003-2018, the study finds that trade competition and complementary relations coexist, the economic structures are similar, there are higher trade competitiveness and higher trade complementarity in exports, great potential of intra-industry trade with horizontal division in steel, machinery and transportation equipment, textiles and clothing and so on, between China and ASEAN emerging economies such as Singapore, Thailand, Malaysia and Vietnam. There is big economic gap, lower trade competitiveness and higher trade complementarity, a huge potential for inter-industry trade in the vertical division in the fields of steel, machinery and transportation equipment, textiles and clothing and so on, between China and ASEAN developing countries such as Brunei, Myanmar, Cambodia, Indonesia, and Laos. Finally, it puts forward the comprehensive opening path of spatial integration and expansion, the coordinated growth path of industrial complementary development, the two-way smooth path of trade logistics development, and the policy communication path of regional coordination mechanism.