Abstract: Semantic accessibility scale can be considered a fully-understood measure of natural language texts.This essay，on the basis of methods of automatic text summarization system and literary style analyses，puts forward a formula by which data-based SAS originating from English literature texts can be evaluated on line.It is by means of discussion about the corpus from The Old Man and the Sea written by Nobel winner that the conclusion testifies to the fact that no distinctiveness among different sampling ratios can be discovered.Despite the existence of domain limitation，domain simplicity and relativity of evaluation on line，SAS formula will benefit the literary critics who have access to internet-based English texts.

摘要： 语义接受度（SAS）是衡量自然语言文本可理解程度的标尺。通过结合自动文摘系统评价方法和文体学分析方法，提出了可用于在线分析英语文学文本SAS的系统评价公式，并通过诺贝尔文学获奖作品《老人与海》的语料分析验证了公式的可适用性：不同的抽取率不会引起评价值的显著差异。尽管存在域的有限性、域的单一性和在线评价相对性等不足，此公式为文学评论者借助网络进行英语文本SAS在线评价提供了便利。