With the semantic variation of catchwords after 2000 as the research object, this paper studies their structural features,semantic features, syntactic features, and their relevance with metaphors. Important findings include: 1. In terms ofstructural features, techniques of ellipsis, double syllables, humor etc can be found in these catchwords, and catchwordsmade up of neologism are in violation of structural rules and co-occurrence rules; 2. Semantic variations of the catchwordsmay come either from interaction with other components so as to produce new syntactic functions or by breaking thenorms (such as “not knowing one’s own employment”) . 3. Semantic variations in catchwords can also be caused by theuse of metaphors as well as word structure variation and syntactic variation.