Abstract: The paper explores the social identity of naturalized footballers in China by analyzing replies extracted from the relevant trending topics on Weibo in a diachronic manner. A mixed-method examination of these replies through manually annotated sentiment analysis and theme extraction reveals that: 1) Sentiments about the social identity of naturalized footballers polarize significantly, among which negative emotions being more intense than positive ones; 2) sentiments toward different players are quite diversified; 3) sentiments change markedly from negative to positive over time; 4)“nation and ancestry”,“acculturation and integration”and“competitive level”are the three most discussed themes of online conversations about naturalized players.