名词性成分有多重指称意义,其定指性意义与名词短语的类型、句法位置和语用因素存在着紧密联系。本文从词汇、句法结构两个层面分析汉语中定指和不定指成分的表现形式,并通过语用理论对两者在表达形式上的差别进行解释。结论表明,预设是构成区别的主要因素,名词性成分指称对象的信息状态,及其内在的信息分布结构决定了说话者对名词短语类型的选择。 Nominal components have multiple referential meanings, and their definite meanings are closely related to the types, syntactic positions and pragmatic factors of noun phrases. This article analyzes the expression forms of the fixed and indefinite components in Chinese from two levels of vocabulary and syntactic structure, and explains the differences between the two forms through the pragmatic theory. The conclusion shows that the presupposition is the main factor that makes up the difference. The information state of the alleged component of the nominal component and its internal information distribution structure determine the speaker’s choice of the noun phrase type.