Spherical MgCl

2

-supported Ziegler-Natta catalyst is one of the most widely used industrial polyolefin catalysts. The property of such catalyst is intensively influenced by the preparation technology

so the preparation process is important to research. In this paper

the spherical polyolefin catalyst was prepared by the reaction of spherical MgCl

2

support with TiCl

4

.The Ti content

specific surface area

specific pore volume and crystalline form of intermediates in the reaction process were analyzed. The effect of dibutyl phthalate as internal donor in such process was also investigated. The result of this experiment provided an important reference for the preparation of spherical MgCl

2

-supported Ziegler-Natta catalyst.