The present article is a corpus-based contrastive study on mitigation of criticism in linguistic book reviews in English and in Chinese. It is based on the face theory of Brown and Levinson (1987) and follows the framework of Johnson and Roen (1992). The present article shows the following results: (1) at the local level, there are thirteen mitigation devices in the corpus, of which only six have been introduced by previous studies; devices of ‘generalization’ and ‘metaphorical statement’ are specific to the English sub-corpus, whereas ‘omission’ is only found in Chinese; (2) at the global level, English writers maintain an overall supportive tone with praise largely distributed in both openings and closings, whereas their Chinese counterparts sound much impartial. Differences in findings are then explained from perspectives of cultural values and functions of book reviews.