Abstract: The general knowledge of English pronunciation and intonation are introduced. To explore the ways to improve the domestic English learners’ pronunciation and intonation, besides, to help learners better handle the speech prosody, especially in sentence stress and rhythm, an objective evaluation system of English sentences is established, which extracts the energy characteristics, marks the stressed syllables, and evaluates the test sentence by using the improved PVI（Pairwise Variability Index）.

Key words: pronunciation and intonation, stressed syllables, prosody, energy characteristics, Pairwise Variability Index（PVI）

摘要： 介绍英语语音语调相关知识，根据国内英语学习者现状，研究基于重音与韵律的英语句子客观评价系统，通过提取语音的能量特征，对英语句子进行重音划分，使用改进的成对变异指数（Pairwise Variability Index，PVI）算法作为句子评价核心，旨在提高说话人对英语句子的重音与节奏的把握。

关键词: 语音语调, 重音, 韵律, 能量特征, 成对变异指数（PVI）