This paper is a case study of the pause frequency characteristics of professional interpreters’ English-Chinese (EC) simultaneous interpreting without text. The VOA live EC simultaneous interpreting of Donald Trump’s presidential inaugural speech is selected as the case, based on which a small-size bilingual parallel corpus with double modalities is built. A comparison of pause frequency and its chi-squared test is made through SPSS between original speech and the EC simultaneous interpretation, whose result shows that the pause frequency in simultaneous interpretation is bigger than that in original speech. The above quantitative analysis is followed by an in-depth qualitative one under both audio and text modalities concerning those pauses in the corpus, the result of which finds five operation modes as follows causing pause frequency increase in Chinese interpretation: 1) loosening of compact structures; 2) segmentation of long information structures; 3) production of interpretation in batches; 4) co-occurrence with paralinguistic features; 5) strengthening of communicative effects. Findings of this research may provide some insights for teaching and practice of simultaneous interpreting while adding to the knowledge of its cognitive process.