Carbon nanotube (CNT) has unique hollow tubular structure, high surface area, easy modification and other excellent properties. Using them to modify polyurethane (PU) can significantly improve the electrical conductivity, thermal conductivity and electromagnetic shielding properties of PU materials. However, the surface of CNT itself is inert and prone to agglomeration, making it difficult to disperse evenly and stably in PU substrate. Therefore, in recent years, in addition to the study of the chain structure of polyurethane itself, researchers have made continuous attempts in the modification of CNT and achieved relevant results. In this paper, the functional group modification of CNT was emphasized, and the applicability and possible shortcomings of each modification method were discussed. It was pointed out that the dispersion of CNT in PU and its interfacial compatibility with PU substrate were still the key to improve the properties of the composite.