Nominalization metaphor,as an important feature of English of Science and Technology (EST),plays an important role in scientific discourse.It performs many discourse functions,such as adding objectivity,concentration,formality,conciseness,cohesion and coherence to English discourse.A good study of the functions of nominalization in EST can help us understand the deeper semantic meaning,and lay a sound foundation for the correct understanding of EST,and provide better service for the translation of EST.