The inter-temporal and low-cost advantages possessed by digital technology have created favorable conditions for cross-border enterprise business communication and collaborative production. From the perspective of cross-border e-commerce, this paper adopts the TOPSIS entropy value method as a method for constructing the digital economy index to evaluate the level of digital economy development in several countries. On this basis, it constructs an evaluation index system for the level of high-quality development of foreign trade and uses the system to measure the level of high-quality development of foreign trade in RCEP countries. Then, we improve the traditional trade gravity model and set the evaluation model of the impact of digital economy on national trade and select variables based on RCEP countries. Taking China-RCEP trade as the experimental object, the validity of this paper’s model is tested by using benchmark regression test, heterogeneity analysis and stability test. The influence coefficient of R&D investment factor on the trade competitiveness of Chinese industries is 1.566, which indicates that strengthening R&D investment in the digital economy era can improve the international trade competitiveness of Chinese industries.