In the recent over 20 years, the Historical Cognitive Linguistics is gradually developing by blending Historical Linguistics, which has more than 200 years history, with Modern Cognitive Linguistics. Cognitive Linguistics has the tradition using the “usagebased model” to study the motivation in the linguistic facts, which makes Historical Cognitive Linguistics have the natural advantage of blending with Corpus Linguistic to observe related language phenomena and the historical change process of linguistic structures, and to search for the law of diachronic change of linguistic facts. This paper specifies the functions of COHA in studying American words, morphology, syntax, semantic and culture, etc, which illustrates the COHA expanding the horizon of Historical Cognitive Linguistics, and COHA also provides a powerful tool for Historical Cognitive Linguistic research. 