Pragmatic identity construction is conducive to achieving communicative purposes. And political discourse is an effective means of promoting international communication. While the construction of identity in the field of pragmatics is rarely discussed in political discourse. To better understand the political intention of speakers, the research explores how and what pragmatic identities are constructed in political discourse based on pragmatic identity theory, and takes the Keynote Speech by Xi Jinping at the Opening Ceremony of the Boao Forum for Asia Annual Conference 2022 as corpus. It is found that this speech included many derived identities from pragmatic identities. And President Xi Jinping chooses and exchanges his derived identities from various pragmatic identities by using the strategies of the personal pronoun and linguistic adaptation theory, which helps him better switch his pragmatic identity and achieve his interpersonal functions or political functions.