Abstract: Among all learner factors,self-confidence is one of the most salient ones.Learner's self-confidence has a close relationship with his L2 acquisition.Different degrees of self-confidence may form two distinctive learning circles:a virtuous one and a vicious one. To ensure a virtuous learning circle,college English teachers should try to cultivate an ideal learning environment;to tailor varying teaching methods to individual students and to bosom dual aims in his (her) teaching-linguistic education and "personhood" education.