This paper adopts 24 indicators from four levels, that is, the competitiveness of cross-border tourism socio-economic environment, the competitiveness of cross-border tourism market, the competitiveness of cross-border tourism basic conditions, and the competitiveness of cross-border tourism sustainable development potential. And then, it constructs an evaluation system for cross-border tourism competitiveness of national key development and opening up pilot zones, and measures and evaluates the cross-border tourism competitiveness and its influencing factors of 9 National Key Development and Opening up Pilot Zones in China. The study shows that there are differences in the cross-border tourism competitiveness of 9 National Key Development and Opening up Pilot Zones in China, and their influencing factors are different. The level of openness, tourism resources, and service facilities are the main factors affecting the development of cross-border tourism. Based on this, in the future, it is of great necessity to adhere to high-level development and opening up, deeply explore featured cross-border tourism resources, fully leverage the "first try, first pilot" preferential policies, focus on the advantages and characteristics of key experimental areas, and further enhance the competitiveness of cross-border tourism in National Key Development and Opening up Pilot Zones.