A series of liquid crystal polymers(LCPs) with X-shaped two -dimensional mesogenic units has synthesized via low temperature solution polycondensation.The liquid crystalline behaviors of the polymers were characterized using differential scanning calorimetry,polarized microscopy and X-ray diffraction.It was found that all the polymers show nematic thermotropic liquid crystalline characteristics,and their melting temperature T_m and isotropization temperature T_i change regularly with varying of the length of the flexible spacer and of the side groups