From the perspective of semogenesis, this paper puts forward a pragmatic framework to give a new explanation of grammatical metaphor. The pragmatic framework mainly consists of two factors, that is, register and speaker. Concerning the first factor, the paper argues that grammatical metaphor happens when a lexico-grammatical expression is not consistent with its register, which will lead to certain pragmatic meaning. Concerning the second factor, it is contended that grammatical metaphor results from speaker construes experiences by changing reference point to satisfying his communicative intention. This new explanation of grammatical metaphor puts emphasis on the practical use of linguistic expressions and highlights the critical role that pragmatic features play in identifying grammatical metaphor.