情态助动词属于表达说话者观点和态度的一类词，是语法研究的热点话题。本文从时间状语、否定、句法成分移位等五个方面探讨了汉语情态助动词的词汇范畴，并分析了其句法特征。情态助动词可以被时间状语、否定词和副词修饰，允准其后的谓词宾语移位或删除，可以构成“A-not-A”句式，属于真谓宾动词的一类。这类词以主谓结构或其它谓词结构为宾语，在能否带时态助词、能否单说等形态上区别于其它真谓宾动词。
Modal auxiliaries express the speakers’ attitudes and opinions and are a hot topic in grammar studies. This paper analyses the lexical category of modal auxiliaries in Chinese from five aspects, such as temporal adverbials, negation, movement, and further studies the syntactic features of modal auxiliaries. Modal auxiliaries could be modified by temporal adverbials, negative words and adverbials, could license the move and deletion of predicate object, and could form “A-not-A” construction, so they are true predicate verbs. Modal auxiliaries also take subject-predicate structure or other predicate structures as complement, and differ from other true predicate verbs in tense particles and syntactic independence, etc.