Despite that language learning strategy(LLS) has been heatedly discussed since its emergence in 1975, its conceptualization, categorization and strategy training models are still in dispute. However, what commonly revealed by most studies is that there is a positive correlation between the use of language learning strategy and language learners' performance. This paper applies Dornyei's classification, known as cognitive strategies, metacognitive strategies, social strategies and affective strategies. By reviewing previous studies on the application of metacognitive strategy in English as a second language(ESL) reading comprehension, plenty of useful implications for reading pedagogy are suggested. It further explains how certain important metacognitive strategies, namely Semantic Mapping(SM) and Experience-Text-Relationship(ETR), can be implemented in second language reading comprehension, aiming to encourage language learners to be aware of learning strategies,"learn how to learn"(Cohen, 1988, p66)!