Tones are categorized as super segmental elements which can distinguish meaning in some languages such as Chinese, Vietnamese. While in some other non-tonal languages such as English, French, tones are utilized to express the emotions of the speaker or to form interrogative sentences.Many researches have probed into the effect of L1 on L2 perception and production extensively in many aspects. However, the effect of L2 on L1 is still less known and not be studied broadly and thoroughly. Tone judging tasks are adopted as the main method to explore the influences of L2 on L1. The conclusion is that immersion English environment will slightly weaken Mandarin speakers’ original tone perception sensitivity as L1 words retriving speed becomes slow.