The poetry of Tang Dynasty is of great variety in style.Since the preceding understanding of its prosody is limited,there have been certain mistakes.This paper tries to analyze this issue in three aspects: Firstly,the long sentence,mainly used to name the seven-character metric poems;Secondly,the creative writing of seven-character metrics in Tang dynasty with the conclusion of being "not rare",but common with prominent features;Thirdly,a varied examination of the mixed metrics in middle Tang dynasty with t...