"Maekgyung(脈經)" was the first book for diagnostic method in traditional Chinese medicine history, but it couldn't be spreaded widely. After that, "Maekgyeol(脈訣)" was widely spreaded for centuries, because it was more concise and easier to memorize than "Maekgyung". But as time went by, people got to know that "Maekgyeol" had many errors. After "Maekgyeolganoh(脈訣刊誤)" corrected the errors of "Maekgyeol", "Maekgyeol" came to lose its reputation and people began to study "Binhomaekhak(瀕湖脈學)" instead of "Maekgyeol". We got to wonder why "Maekgyeol" was criticized by many people, so we decided to compare the definitions of pulses(脈象) in "Maekgyung" and "Maekgyeol" and "Maekgyeolganoh". Both "Maekgyung" and "Maekgyeol" have 24 kinds of pulses, but 22 kinds are in common. In 22 kinds of pulses, only 2 kinds of definitions are similar and the others are different. And "Maekgyeolganoh" criticized errors of "Maekgyeol" and corrected the definitions by that of "Maekgyung". In conclusion, we come to know that "Maekgyeol" was rejected by people because it defined most of pulses different from "Maekgyung".