The study takes the use of the pronoun “Benzun(本尊)” as research object, using BCC corpus we have made an investigation and analysis of some related materials. Firstly, we focus the discussion on the semantic and pragmatic analysis from the synchronic angle. Secondly, we explore the grammaticalizational process of “Benzun(本尊)”. Lastly, we explain the main reasons of formation and the use of the pronoun “Benzun(本尊)”.