Mood,tone and modality are the three main devices to realize interpersonal meaning in functional grammar.This paper aims to explore the functional meanings of Chinese honorific addressing term "Jun" in Three Hundreds Poems of The Tang Dynasty in perspective of functional grammar.The conclusions are as follows:The honorific addressing term jun has multiple semantic potentials with the functions of profiling the addressee's distinguished social status as well as expressing the addresser's respect and politeness,therefore it can be treated as a practical device to shorten the psychological distance between the two sides in communication and to create a good atmosphere for interaction.The honorific term "Jun" is a preference choice for ancient poets to realize interpersonal meaning.