Tone is one of the most prominent, distinctive, and significant properties of the Chinese language. In the realm of tone sandhi, one of the most interesting phenomena is the Tone 3 sandhi (T3). T3 sandhi is one of the rules in the phonological change, a low T3 syllable inevitably changes to a rising tone (T2) when it is followed by another T3 syllable. This study aims to investigate the underlying mechanism of the third tone (T3) sandhi in Mandarin Chinese, comparing the acoustic features in both real words and pseudowords. The current study employed a qualitative descriptive method and PRAAT6310 acoustic analysis software. The findings of the study demonstrated that T3 sandhi in real words of the Chinese language resembles pseudowords and is likely computed naturally in a phonological cognition process. This research provides an important reference value for research in the fields of tonal variation in Chinese language and language acquisition.