Intelligent Diagnosis for pathological voice contains two parts. One is intelligent detection, and the other is intelligent comprehension. Before the application of intelligent comprehension, it is important for us to know how human perceive pathological voice. This paper first investigated acoustically a patient who had vocal cord polyp read Chinese characters with Mandarin tones before and after the surgeries. Second, identification test was used to find out the effect of vocal cord polyp on Mandarin tones recognition. The results show that first, the effect of vocal cord polyp on Tone 1 and Tone 3 in F0 contour are statistically significant, but not Tone 2 and Tone 4. Second, vocal cord polyp does not affect identification of Mandarin tone types. Third, vocal cord polyp affects Tone 1 and Tone 2 in identification rate significantly, but not Tone 3 and Tone 4. It is concluded that vocal cord polyp has little influence on the intelligibility of Mandarin tone types. And our research results are referential to intelligent diagnosis for pathological voice.