As the global division of labour system enters a period of accelerated restructuring, how to use the new generation of digital technology to achieve high-quality development of China's export trade has become a key requirement for promoting a new development pattern of domestic and international double-cycle. Based on the technological complexity of China's exports in 30 provinces from 2012 to 2020, the article uses entropy-weighted TOPSIS to measure the level of development of provincial digital economy, and provides an in-depth analysis of the impact of the digital economy on the technological complexity of China's exports and the underlying mechanisms. The study finds that the digital economy significantly contributes to the technological upgrading of China's exports; this enhancement effect is most obvious in the eastern region, but has a negative inhibitory effect on the export quality in the western region. From the perspective of the impact mechanism, the digital economy promotes knowledge spillover and accelerates the marketisation process to achieve export technology upgrading; however, the development of the digital economy leads to labour degradation and hinders export technology upgrading; from the perspective of industrial transformation and upgrading, the digital economy accelerates the technological upgrading of export products through the advanced industrial structure, but does not have a significant impact on the rationalisation of industrial structure. Further tests show that the effect of the digital economy on the upgrading of export product quality is more prominent in low- and medium-technology industries. The findings of the article provide data support and analytical perspectives for exploring the use of the digital economy to lead the development of trade innovation and enhance the international competitiveness of China's foreign trade, and provide new ideas for exploring the improvement of the quality of China's high-quality external circulation development in the context of the digital economy.