Pai-sha-tun is Located in the west coast of Miao-li County in Taiwan. The residents emigrated Taiwan since more than 200 years ago from their motherland Tou-pei, a small town in Huei-an, Chuan-chou, Fukien. They live on farming primarily, and fishing secondarily. Adjoining to Hou-long on the north, a mixed-dialect of Chang-chou dialect and Chiuan-chou dialect of Southern Min, and Tong-hsiau on the south, a Chang-chou dialect, Pai-sha-tun dialect has been greatly influenced by this two dialects, and become a mixed dialect on initial and rhyme, but retain some tonal features of Chiuan-chou dialect. Based on phonemic analysis, Ang Uijin (1985) argued that there are three registers in General Taiwanese. But the tonal system of Pai Sha Tun dialect consists of four registers, which is very special in Taiwanese Southern Min. Generally speaking, Min dialect owns a complicated tone system. There are a basic tone and a sandhi tone every tone category in Taiwanese Southern Min. The features of tonal system in pai-sha-tun dialect can be depicted as follows. 1.The sandhi tones of rising, upper falling, and lower entering are all mid-high level. 2.For tones of upper even, lower even, lower falling, lower entering, there are two alternations depending on the tone value that follows. (1)If what follows is not a low level tone, the sandhi tone will be mid-low level. (2)If what follows is a low level tone, the sandhi tone is assimilized as a low level tone. This paper is aimed to describe the special tonal system and the rules of the tone sandhi for the Pai-sha-tun dialect.