Metaphor research is an important issue in the field of contemporary language philosophy. Davidson’s What Does Metaphor Mean is a key work worthy of attention. His metaphor research questioned the argument of semantic interaction theory, and proposed his own metaphor theory. He believed that metaphor has its own strict and ordinary meaning. It cannot be completely interpreted in an overall sense. This paper analyzes the philosophical thoughts like metaphor and the world, metaphor and cognition, the pragmatic view of metaphor, the function and application of metaphor, etc. On this basis, it is deduced that the fundamental reason why metaphor has become a time-honored topic in language research is “to convey infinite meaning with limited words”. This core essence makes metaphor a subject to be discussed and tackled by multiple disciplines such as poetics, cognitive psychology, computational linguistics, and intelligence science. Therefore, the academia should give Davidson’s metaphor theory its due historical status and new academic value.