This study is centered on the application of metaphor theory to math education from the cognitive-linguistic view. This study, at first, introduced what metaphor is, and looked into it from the math-educational view. Furthermore, on the basis of that, this study examined the significance of metaphor to math education, and dealt with its relevance to math education, focusing on the functions that metaphor has. This study says that metaphor has the function of explanation, elaboration and representation. In addition, this study examplifies that using metaphor can be an effective math learning strategy for mathematical concept explanation, mathematical connection and mathematical representation learning.