This paper studies the impact and mechanism of urban Internet development on the market power of export enterprises. Based on the urban Internet infrastructure, the scale of the Internet users and Internet application capacity, the urban Internet development index was comprehensively constructed, and the Internet development level of 161 cities was matched and measured by using the data of 959 Chinese A-share manufacturing export enterprises from 2013 to 2018. The research shows that the development of the urban Internet has significantly improved the market power of China's export enterprises measured by price addition through “innovation effect”, “cost effect” and their joint action, in which “innovation effect” plays a greater role. Then this study carried out the heterogeneity test of enterprise factor intensive type, ownership and location. This paper not only promotes the understanding of the economic effects of the construction of new network infrastructure, but also brings inspiration for export enterprises to achieve high-quality development of foreign trade and strengthen the integrated application of the Internet.