Disclosed is a method of producing a cyclic olefin polymer having a polar functional group, an olefin polymer produced by using the method, an optical anisotropic film including the olefin polymer, and a catalyst composition for producing the cyclic olefin polymer. In the olefin polymerization method and the catalyst composition for polymerization, since deactivation of the catalyst due to polar functional groups of monomers is capable of being suppressed, it is possible to produce polyolefins having a high molecular weight at high polymerization yield during polyolefin polymerization. Furthermore, the cyclic olefin having the polar functional groups has excellent polymerization reactivity and the activity of the catalyst composition including the same is maintained under a variable polymerization condition. Accordingly, the present invention is very useful for a mass-production process.