Polymerization catalyst is fundamental to the production of polyolefins, including polyethylene and polypropylene. In fact, final polymer product properties are determined via the catalyst system and further optimized by the specific polypropylene process. It is a catalyst for bulk polymerization or vapor phase polymerization, which has a high catalytic activity in bulk polymerization or vapor phase polymerization. When it is used in the presence of a small amount of hydrogen, gives an olefin polymer having excellent melt flowability and stereo regularity.