中、下寒武统界线研究是至今尚未圆满解决的全球性难题.这是早寒武世到中寒武世全球范围存在两个不同的生物地理分区的结果.尽管目前研究从古生物方面进行了大量的工作,也取得了大量的成果,但是它们同样由于存在大西洋生物区和印度-太平洋生物区生物组合不同的影响,目前还没有一个能进行全球性对比的生物组合.因此,寻找其他的中、下寒武统界线全球划分和对比方法是解决中、下寒武统界线难题的途径.对贵州台江中、下寒武统界线剖面的凯里组疑源类进行系统研究,利用疑源类划分了中、下寒武统界线,所划分的界线与三叶虫带划分的界线基本一致,并可与西伯利亚、欧洲在地台上利用疑源类划分的中、下寒武统界线可进行对比.在此基础上,利用全球性早寒武世到中寒武世过渡期间有一个明显的碳同位素负异常来划分中、下寒武统界线,并与西伯利亚、北美中、下寒武统界线上的碳同位素负异常进行对比.这一新的碳同位素划分对比中、下寒武统界线的方法,有助于解决中、下寒武统界线这一全球性难题,也说明了早寒武世末三叶虫动物大绝灭与这次碳同位素负异常有密切的关系. The study of the Middle and Lower Cambrian boundaries is a global challenge that has not been satisfactorily solved to date, as a result of the existence of two different biogeographical sub-regions from the Precambrian to Middle Cambrian world-wide. A great deal of work has achieved a great deal of success, but at the same time, due to the different influences of the biological assemblages of the Atlantic Ocean and the Indo-Pacific Biota, there is currently no biological assemblage for global comparison. Therefore, The global division and contrasting of the Lower Cambrian boundary line is a way to solve the Middle and Lower Cambrian boundary problems.A systematic study of the Kaili formation of the Middle and Lower Cambrian boundary line in Guizhou Province is carried out systematically, The division of the Middle and Lower Cambrian boundaries, the dividing line with the Trilobite division is basically the same line, and Siberia, Europe on the platform using the suspected source division of the Middle and Lower Cambrian boundary line On the basis of this, we use the negative anomaly of carbon isotopes during the transition from the global Early Cambrian to Middle Cambrian to divide the middle and lower Cambrian boundaries, Liar, North America, and the Lower Cambrian boundary.The comparison of the new carbon isotopes between the Lower Cambrian and the Lower Cambrian boundaries helps to resolve the Middle-Lower Cambrian boundary A global problem also shows that there is a close relationship between the extinction of the trilobites and the negative carbon anomaly at the end of the Early Cambrian.