Abstract: As the ability to monitor and control one's cognitive processing ，metacognition is fundamentalto language learning. To explore the structure of metacognition anadl its relationships with online presencein college English learning community of inquiry，312 freshmen were measured with scales.'The resultsshowed that : 1) Metacognition was composed of self-rnegulation aad co-regulation;2) 'Teaching presencecan predict cognitive presence ; 3 ) Self-regulation，co-regulation and social presence served to mediatethe effects of teaching presence and cognitive presence.The research suggested that ，in order to buildand develop the blended college English leaming community of inquiry，attention should be given to thekey role of teaching presence，leamers’metacognition should be lrought into full play and socialpresence 's positive effects on interactive language learning envitonment should be enhanced.

Key words: community of inquiry model, online presence, metacognition