A liquid crystalline phase has been discovered in a polyolefin of poly(methylene-1,3-cyclopentane) (PMCP) having, low molecular weight, which was obtained with cyclization polymerization of 1.5-hexadiene (HD) using a zirconocene catalyst in the presence of chain transfer reagents. PMCP clearly shows fluidity and birefringence above the glass transition temperature under the ambient conditions. Schlieren-like texture. which indicates nematic liquid crystalline phase, has been detected in places. Clear diffraction pattern is observed in wide-angle X-ray diffraction analysis below the isotropization temperature. The isotropization temperature decreases with decreasing of weight of the PMCP. PMCP with the higher molecular weight takes the longer time for liquid crystallization from isotropic phase. Non-Newtonian viscosity region in the range of low share rate, which is it characteristic of liquid crystal, has been detected below the isotropization temperature.