Ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) catalyzed by titanium tetrachloride adduct complexes such as TiCl4 . 2L [L = pyridine (1), 2-methylpyridine (2), 2,4,6-trimethylpyridine (3), 3-aminopyridine (4), 2-hyroxypyridine (5)] and CH3Li as cocatalyst was reported. The polymer was characterized by IR and H-1-NMR methods. Five influencing factors were also discussed. The catalyst systems TiCl4 . 2L/CH3Li (L = 2-methylpyridine, 2,4,6-trimethylpyridine) appeared to be very active for the ROMP of DCPD.