The main objectives of the study are to further explore the connection between conceptual metaphor and the language expression structures through the comparative analysis of the conceptual metaphor in the commencement speeches of universities between English and Chinese. It also studies the meaning, cultural characteristics, similarities and differences of the two languages so that it can give a proper interpretation of how the cultural factors works on the language structure and semantic expressions. The conceptual metaphor was regards as a system of human conceptualization. Speeches addressed on graduation ceremonies by great people who are admired by the university students play a vital role in their lives. So the comparative study of conceptual metaphor in Chinese and American commencement speeches is necessary.