This paper focuses on the tone issue of Taiwanese, mainly the phenomenom that "tone 7 spoken as tone 3" and "the sandhi of tone 7 spoken as tone 2" in the Hai-khau accent of the Tsuan-tsiu accent are both correct, and the latter is probably influencd by Mandarin. The paper is divided into 5 sections:a). Some say that "tone 7 is spoken as tone 3" and "the sandhi of tone 7 is spoken as tone 2" are wrong, but the people from Lok-kang do speak this way.b). Some of the sandhi of tone 7 is spoken as tone 2, and some words in tone 7 is spoken as tone 3 (but there is tone 6 in the Hai-khau accent). The reason is that there is tone 6 in the Lok-kang accent, but there is no tone 6 in the Tsiang-tsiu accent. If the basic tone is tone 6, the sandhi will be tone 6, but if the basic tone is tone 7, the sandhi will be tone 6. But there are some exceptions.c). Changes in the language: Mandarin is spoken dominantly in Taiwan. Therefore, some young people are influenced by Mandarin. The sandhi of tone 7 is spoken as tone 2: "inn7-tiunn2" is spoken as "inn2-tiunn2."d). To prove the theory of "no distinction between im(yin) and iong(yang) in the falling tone of the Tsuan-tsiu accent" with examples from four kua-a (traditional songs) booklets.e). The tone systems of the Tsuan-tsiu accent and Tsiang-tsiu accent are different; therefore, the teaching of the two systems should be seperated, to avoid confusion and misrepresentation.