Abstract: Coal pitch powder as filler was added to polyurethane in order to prepare a waterproof material. The mechanical properties，waterproof performance and cryogenic flexibility were determined and the influence of such factors as coal pitch powder’s content and particle size on the waterproof material properties was investigated. Additionally，the interaction mechanism between coal pitch powder and polyurethane was investigated by studying the micro-morphology of the water-proof material with SEM. The measurements of the heat-resistance and Tg temperature of the waterproof material were carried out respectively by TG and DSC. The result indicated that the properties of the waterproof material can satisfy all the requirements of Chinese National Standards for polyurethane waterproof material. When the content of coal pitch powder varied from 10% to 15%, the smaller the coal pitch particle size，the better the mechanical performance；meanwhile good heat-resistance and cold-resistance were also observed.