Tetrasyllabic words represent a particular morphological pattern in Chinese and even in Sino-Tibetan languages in general.In Chinese,coordinating tetrasyllabic words are particularly typical and highly productive.This paper focuses on the"verb-object+verb-object"and"attribute-head+attribute-head"forms of tetrasyllabic words and discusses their origin and features from a diachronic perspective.In Archaic Chinese,there existed various types of coordinating tetrasyllabic phrases.In literature produced from the Wei and Jin dynasties to the Sui and Tang dynasties,coordinating tetrasyllabic idioms started to occur and were relatively fixed in meaning but flexible in form.It was during the Ming and Qing dynasties that coordinating tetrasyllabic words began to be used as a lexical unit.In nature,coordinating tetrasyllabic words are evaluative with a strong subjective feature.