Abstract: Trade costs and technological innovation are the core elements affecting trade behaviors.From the perspective of the theoretical mechanism by which the digital economy affects inter-provincial trade,the digital economy relies on the Internet,artificial intelligence,big data and other information technologies to break the time and space constraints,enhance the effectiveness of information and the matching efficiency of elements,and help reduce trade costs and promote knowledge spillover to promote inter-provincial trade.The empirical test results show that:First,the development of digital economy can significantly promote inter-provincial trade outflow in the province.Second,there is a significant structural heterogeneity in the promotion effect of digital economy on inter-provincial trade.Third,the increase of inter-provincial trade outflow is mainly caused by the decrease of trade costs and knowledge spillover brought by the development of digital economy in the province,and the mechanism of reducing trade costs is more obvious.Fourth,the development of inter-provincial trade in neighboring provinces can promote the trade outflow of the province,while the development of its digital economy will have a negative spatial spillover effect on the trade outflow of the province.

Key words: digital economy, inter-provincial trade, trade costs, knowledge spillover, spatial spillover effect