This study described Japanese language learning assistant system that facilitates learning by supporting students to construct the relation diagram between sentence patterns and vocabulary extracted from Japanese-language grammar. From preliminary survey, we have learned that non-native Japanese language learners, say, Chinese students, are inclined to give priority to the meaning of language, which will obstruct understanding and cause the misuse of language. Consequently, this study proved the effect of Japanese language learning assistant system in supporting Japanese-language learning and strengthening understanding. This study first extracted 555 sentence patterns and 440 word items, and compiled the database on the basis of part of speech. Then the Japanese language learning assistant system was constructed with reference to extracted database. The result shows that learners are more engaged in constructing the relation diagram and the description of sentence patterns and vocabulary by actively communicating with teachers. In comparison with traditional class on lectures and textbooks, there is a significant increase in the average scores of students learning with the assistance of this system.
