通过实例分析，首先说明了为保证准确无误地表达设计意图，将体现设计意图和零部件使用功能的关键要素－设计基准，在图样中明确标注聘为的必要性，并结合实践情况，提出了一套既方便，又不便图样复杂化的标注方法，即在设计基准要素上，直接标注设计基准符号的方法，以及在计算机绘图中实现标注的解决方案。由于标注设计基准后，基准位置一目了然，因而从根本上避免了因未标注设计基准所产生的各种问题，如，无法准确表达设计意图、读图困难耗时、易误解等。此外，采用该标注方法在图样中标注设计基准后，还可有效解决诸如多种尺寸公差并存、未注公差与注出公差不统一等诸多问题。

The paper, by means of illustrations, demonstrates the necessity of marking definitely design data in drafts, because these design data are the key factors of the embodying the intentions of the designer and the functions of components and parts. In combination with what may occur in practice, the author, as well, puts forward a set of approach that can be used conveniently without complicating the drafts .The approach is used to mark directly design data symbols consisted of signs and codes on the design data elements in drafts and the solution to the of marking of the design data symbols in computer aided drawing. After marking the design data symbols(two or three the symbols only) in drafts, the draft users will know where the design data are at once. Therefore, all kinds of the problems, which arise from the design data not having been marked in drafts, will be solved entirely. Meanwhile it points out when the design data symbols are marked directly on the design data elements of components and parts in drafts, other various problems like the conflicts of many kinds of dimensional tolerances coexisting in a same draft, the disagreement between noted dimensional tolerances and unnoted dimensional tolerances in a same one will be solved effectively.