Since the cognitive revolution in the 1970s, metaphor research has made fruitful achievements. However, the existing theories of metaphor interpretation lack interface exploration with pragmatic factors, and cannot effectively explain how the meaning of a metaphor is generated. Ad hoc concept, as an innovative development in the relevancepragmatic perspective, elaborates the core mechanism of meaning construction in the interpretation and comprehension of metaphor. This is of vital importance to the development of cognitive metaphor theories. On the basis of teasing out the progress of metaphor explanation and understanding oriented by Relevance Theory, this study highlights the central role of ad hoc concepts in metaphor comprehension, so as to enrich the theoretical framework of cognitive metaphor research and promote the development of contemporary metaphor pursuit.