Abstract: Four word parallel phrase”is a unique four word structure both in form and in meaning.It is an element between idioms and free phrases.It has such characteristics of fixed phrases in structure,relative stability in form and completeness in meaning.There are two kinds of such phrases:parallel and sequent orders.Its inner word order is arranged by tone iambus(including level beginning and bolique ending,level and oblique tones in order)and four tones sequent arrangements.