This study of the U.S.–China trade war investigated how Beijing (a) uses institutional discourse and rhetoric to conceptualize digital public diplomacy based on the autocratic system of the Communist Party of China and (b) legitimizes its highly centralized and politicized international communication practices. We also investigated how China’s domestic public diplomacy practices affect its international communication. Comparing the online activities of the Chinese Ministry of Foreign Affairs domestically (i.e., Weibo) and internationally (i.e., Twitter) revealed (a) that China first centralizes and politicizes communication content production and distribution to ensure that all messages follow the desired political direction and promote the desired value orientation; and (b) that, although inspired by the network communication perspective, Beijing’s digital public diplomacy emphasizes advocacy and narrative, ignores listening and exchange, and does not seek mutual cross-cultural adaptation. Digital public diplomacy is an instrument that serves China’s internal affairs, controlling and guiding domestic public opinion online to defend Communist Party of China leadership.