This research suggests that valuate similarities by using the matches of patterns which is appeared on different two documents. Statistical ways such as fingerprint method are mainly used for evaluate similarities of existing documents. However, this method has a problem of accuracy for the high similarity which is occurred when many similar words are appeared from two irrelevant documents. These issues are caused by simple comparing of statistical parameters of two documents. But the method using patterns suggested on this research solved those problems because it judges similarity by searching same patterns. This method has a defect, however, that takes long time to search patterns, but this research introduce the algorithms complement this defect.