In recent years, idioms have attracted more and more attention which have become the key point in cross-cultural communication. But the existing research on plant idioms involves less. Therefore, this thesis study from plant idioms in English and Chinese. This thesis analyzes the similarities and differences of plant idioms between English and Chinese and the causes of the similarities and differences. Thus English learners can fully understand the cultural connotation of English and Chinese idioms, and promote the smooth progress of cross-cultural communication.