The paper is concerned with a study of the relationship between the use of language learning strategies and student achievement. Chastain states that all learners have their learning strategies but only some are successful. It aims to investigate the types of grammar learning strategies that Asian learners use and the differences of using grammar learning strategies between the able learners and the less able learners. The strategy inventory for language learning (SILL) developed by Oxford was used to inquire learners' use of language learning strategies. The findings showed that the able learners and the less able learners showed differences in using grammar learning strategies, and the reasons behind are related to their learning attitudes. In addition, the less able learners found few provided strategies useful whereas the able learners believed that a number of strategies are useful in English learning.