Carbon nanotubes of different proportions were added to the cement matrix to prepare cement-based materials, and the thermal expansion property of those materials was measured from room temperature to 600°C. While the materials were characterized by means of DSC/TG, XRD, pore size distribution diagrams, SEM images. The results show that the thermal expansion rate is positive from room temperature to 150°C, there is a slight expansion; the thermal expansion rate is negative and gradually decreases from about 150°C to 590°C, the specimen shrinks continuously. When the blending amount of carbon nanotubes is 0.3%, the thermal expansion curve is always below those with the amounts other than 0.3%, and the thermal expansion rate reaches a minimum value. This shows that when the amount of carbon nanotubes is 0.3%, the hydration reaction is sufficient and a large amount of hydrous calcium silicate gel is produced, and the shrinkage is obvious and the density is significantly improved. Therefore, the content of 0.3% carbon nanotubes can effectively prevent the emerge of abnormal expansion of local area for a heating pipe and therefore, improve the durability of the structure.