This study considered whether the vocabulary list of Korean level 3 textbooks is appropriate for the topics and mastery of the unit. The selected vocabulary list by topic possibly enhances the level of difficulty per unit. A list of vocabulary was chosen, based on the view of preceding studies that indicated that the words commonly included, may be essential to the topic. The study was limited to Korean level 3 textbooks published after 2010, and the vocabulary list for a total of nine types of textbooks was compiled. As a result, seven topics were commonly included in the third-level textbooks: Health, Weather, Love, Character, Travel, Job, and School Life. In this study, a vocabulary list was compiled of words that are contained in each topic. In addition, vocabulary and vocabulary lists were compared to the level of the International Standard Korean Language Curriculum that determines proficiency. As a result, select a list of vocabulary by subject, considering the requirements for mastery at level 3. The study revealed that although there are not many common vocabulary words for each topic that are suitable for Level 3 proficiency, a list of words with meaningful relevance can be selected through sub-topics. Further, it was suggested that a study of topic-specific lexemes was continuously needed to select a vocabulary that considered both proficiency and topic matter when selecting textbook vocabulary.