The paper examines synaesthetic metaphors in eight of Shakespeare’s plays through a statistical analysis from the perspective of cognitive linguistics, with the purpose of exploring the features and cognitive mechanism of synaesthetic metaphors in Shakespeare’s plays. It is found that over 80% of synaesthetic metaphors in the study follow the hierarchical distribution (Ullmann 1958) and projects from an inferior sensorial domain to a superior one, which matches the cognitive mechanism of metaphors put forward by Lakoff and Johnson in 1980. The study also proves the irreversibility of the projection direction in synaesthetic metaphors (William, cited from Less 1999), with only a few violations. And the rare violations reflect Shakespeare’s creative use of synaesthetic metaphors.