-supported Ziegler-Natta catalyst is currently the most widely used industrial polyolefin catalyst. The catalyst is highly active and can produce morphology-controlled polymer. The MgCl
2
support is one of the main components of such catalyst and has an important role in the research of supported Ziegler-Natta catalyst. The MgCl
2
support preparation is one of the key technologies of the catalyst production. In this article
the development of early supported Ziegler-Natta catalyst and the structural features of MgCl
2
as support for Ziegler-Natta catalyst are briefly introduced
with emphasis on the activation and morphology control technologies for preparing MgCl