本文基于中国大学学习者英语口语语料库(COLSEC),通过发音错误标注,对比分析发音替代现象在不同成绩组的学生群体中的分布,调查该现象频率分布的变化与学生水平之间关系。研究发现,发音替代错误总体上可作为区分不同口语水平的重要特征;另发现三类辅音替代错误独立于学生的口语水平,是学生语音学习的主要困难。 Based on COLSEC, this paper compares the distribution of pronunciation substitution phenomenon among students in different grades through the pronunciation errors, and investigates the relationship between the changes of the frequency distribution of the phenomenon and the students’ level. The study found that substitutional errors in pronunciation can be used as an important feature to distinguish between different oral levels. In addition, it is found that the substitution errors of three types of consonants are independent of the students ’oral English, which is the main difficulty of students’ pronunciation.