The present invention relates to a novel metallocene compound, a catalyst composition including the same, and a method of preparing an olefinic polymer by using the same. The metallocene compound according to the present invention and the catalyst composition comprising the same can be used for producing olefinic polymers, have outstanding polymerizing ability, and can produce olefinic polymers of ultra high molecular weight. In particular, when the metallocene compound according to the present invention is employed, an olefinic polymer of ultra high molecular weight can be obtained because it shows high polymerization activity even when it is supported on a carrier and maintains high activity even in the presence of hydrogen because of its low hydrogen reactivity.