《老子》不但是道家、道教的经典，也是中国文化的代表性著作。但是书中未能解决的问题纷繁众多，《老子》道德二篇的篇序排列便是其中之一。在篇序问题上，王弼本、河上公本等传世本都以《道经》为上、《德经》为下。但马王堆帛书却与传世本不同，甲、乙二本都是《德经》在前，《道经》在后。北大汉简《老子》有《老子上经》和《老子下经》的篇名，两篇分别对应传世本《老子》的《德经》和《道经》，正好与帛书甲、乙本篇序一致。本文首先梳理了文献记载的《老子》篇序和学者们研究篇序问题的主要观点，并在此基础上，从古书体例和《老子》一书结构、思想和具体内容上对《老子》的篇序问题进行了研究。本文认为，从古书体例上来看，诸子“其书不作于一时，其先后亦都无次第”，《道》、《德》二篇本为老子在不同时间所作的两篇文章，最初并不是一个整体，无上下之分，没有顺序可言。《道》、《德》二篇外在形式上为两编竹简，而缣书作为书写材料其性质与竹简不同，其容量较大，可以合抄更多书籍；帛书作为一个整体则能固定文本，造成篇序的排列。古书流传多“单篇别行”，《道》、《德》二篇写成之后即单篇流传，后人将其整理结集也会根据自己的取舍排出篇次顺序。二篇最初写成并无篇名，篇名及书名皆出自后人之手。从《道》、《德》二篇的结构、思想和具体内容上来说，二者是相对独立的体系。对比《吕氏春秋》和《淮南子》严密的篇序和精巧的结构，《道》、《德》二篇之间的联系则显得较为松散。作为老子思想体系中的重要概念“道”和“德”，作为“道”的重要特征“无”和“有”，以及“无为”、尚阴守柔守雌的思想都分别分布在《道》、《德》二篇中。但是《道》篇多言道，《德》篇多言德，二者思想本质一致又各有所重，单独来看都能成为独立而完整的老子思想体系，皆言“道德之意”。《老子》书中不少意义相近、句式相同的具体语句多重复出现，通过对具体例子的分析，发现重复内容大多并非《道》篇、《德》篇各自内部的重复，而是其中一篇的内容又出现在了另一篇之中。同时，这些重复内容虽表达的思想一致，但句式或文字都稍有变化，这也反应了这二篇在写作上的时间差。

Lao Tzu is one of the most important Chinese ancient classics，which is also called Tao Te Ching .In terms of the sequencing of the two parts, Tao is the first and Te is the second according to a large number of traditional texts. However, we were shocked by the unearthing of Mawangdui Silk Texts of Lao Tzu, whose sequencing of the two parts is different from the traditional texts. Te is the first part, and Tao is the second. The Bamboo Text of Lao Tzu, which is copied in the Western Han Dynasty, has the same sequencing with Mawangdui Silk Texts.The discussions of this paper are based on the historical documents, educated opinions and the contents of Lao Tzu.In order to solve the contradiction of the parts between traditional texts and excavated texts, we try to come up with some newviewpoints in questions of the part-dividing and the sequencing of the two parts of Lao Tzu from the stylistic rules and the contents both sides.From the side of stylistic rules and layout of Chinese Classics,Tao and Te were written in different times, and one of two parts was circulated not with the other. Originally, the two parts were not in a certain sequence. From the other side,Tao or Te is relatively independent to each other, whether in structure, main ideas or detail content. Tao or Te is also a complete system when it departs from each other.