Abstract: This essay, by use of the grammar theory of the semantic function, from the start of meaning, combining with the language performance, and taking the relation sentence of the static symmetry as the platform, gives a discussion of the semantic character and the syntax performance of the relation word of the static symmetry as well as the static symmetrical relation. Also it uses the symmetrical relation to explain the exchange of subject and object.

Key words: relation word of static symmetry, relation sentence of static symmetry, exchange of subject and object, semantic functional grammar