全浊上声变去声是普通话语音演变的一条规律，但在研究语音演变的例外时发现，除了一部分全浊上声仍读上声外，还有部分去声变上声的现象，而这些去声变上声的字中，却不同于全浊上声向去声演变的情况，去声变上声的现象中声母无清浊的分别，全清、次清、全浊、次浊声母字都有演变成上声的现象。以《广韵》与《方言调查字表》为依托，列出在中古音中读去声而在普通话中读上声的现代汉语常用字，并从方言、谐声字、异读字、诗词押韵等角度来论证上声与去声之间的联系，得出去声向上声转化的合理性，进一步探讨去声演变为上声这一语音现象。

It is a rule of the phonetic evolution of Putonghua that the whole voiced falling-rising tone changes into the falling tone. However, in the study of the exceptions to the phonetic evolution, it is found that in addition to some of the voiced falling-rising tones still read the falling-rising tone, there are also some cases of the change from the falling tone to the falling -rising tone. But it is different from the phenomenon of the change from the voiced falling-rising tone to the falling tone. In this case of the change from the falling tone to the falling-rising tone, the initial consonant has no clear distinction between voiced and unvoiced. Based on Guang Yun and Dialect Character Form, the researcher lists the common characters in modern Chinese, which read falling tone in the middle ancient ages and the falling-rising tone in Putonghua, and demonstrates the relationship between fallingrising tone and falling tone from the perspectives of dialect, phonogram, variant pronunciation words and rhyme of poetry. The study proves the rationality of the transformation from falling tone to falling-rising tone.