This research is for suggesting the correlation between learning strategies used by good second language learners and study achievem ent by comparing learning strategies of the good learners and bad learners. It is proved that firstly, good learners use recognition strategy more than bad learners. Secondly, good learners use self developed strategy compared with bad learners. Thirdly, bad learners don`t use strategy or reward strategy at all when they study Japanese. Fourthly, even though good learners and bad learners use the sam e strategies, they showed significant differences in study achievement. The cause can be found in the num bers of the subordinate learning strategies which they use.