Irreversibility has been always viewed as one of the inherent properties of metaphor. However, not all metaphors in constructions follow this principle. Different from the traditional metaphorical structure "XY", "XYZ" in reversed syntactical structures still has its metaphorical meaning and remains unchangeable, reflecting its unique reversibility. This reversibility of "XYZ" derives from the identifiable semantic structure and the distributional subject-predicate form, constituting an isomeric relation between syntax and cognition. The reversibility of metaphor is neither equal to syntactical equivalence nor identical to cognitive symmetry. Investigations into metaphorical reversibility may shed light on how syntax interacts with cognition from a deep level.