The web platforms of Cross-border Electronic Commerce (CBEC) are important sites for language service implementation. The analysis of its language service is done by observing typical web platforms of CBECs and their language service partners to analyze the language service therein, mostly from its construction mode and service mode. There are four kinds of basic construction modes: self-building, co-building with sellers, with domestic people and with language service providers (LSP). Driven by forces of people, information and technology/tools, the service modes include human translation, crowdsourcing translation, CBEC language service training, machine translation, and post-editing of machine translation. The major problem in the language service of CBEC web platforms lies in their throughput ability of translation data. Other problems are most seen in translation, localization and among co-builders. For now, some tentative solutions can already be given to some of these problems.