The purpose of this study is to show the process of developing “Usage Searcher of Korean Learner``s grammar pattern” in Korean Language Institute of Yonsei University. The searcher is a tool for searching the usage in the learner’s corpus to know how learners use the grammar patterns which is provided in the textbook or the class. The development process of this searcher is the below. First, grammar patterns which will be searched are chosen. These are based on the textbook of Yonsei Korean 1~6. Then target corpus is selected. Yonsei Univeristy Korean Language Institute built ‘2014 Yonsei University KLI Learner``s Corpus’ and for this searcher, 133,785 words is selected among 390,000 words. The target corpus is tagged in morpheme automatically by Utagger. And then, we made searching formulas for every grammar pattern, and revise the tagged corpus according to the formulas for the better searching result. The input part of the searcher is divided into ‘general search’ and ‘representative grammar pattern search’. And there``s a ‘searching in detail’ menu for the specific search in the users`` language and level. The output part of the search shows the file name, mother tongue, and the level of users for each usage, and there``s a ‘full text’ button. This study will contribute the researchers who will study the grammar pattern and errors in Korean language learners.