Lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA) were used as the main phase change materials, multi-wall carbon nano-tube (MWNT)for the framework. All the composite materials were prepared by melt-blending method. Physical Properties, temperature field distributions, heat store and release time, thermal conductivities and resistivities of composites as form-stable phase change materials were characterized by tablet pressing machine, infrared thermal image, thermal conductivity instrument and resistivity meter. The results show that molding pressure and contents of MWNT had no distinct influence on density of composites phase change materials. The four acidic organic matter, adding MWNT with the mass fraction of 24%, 19%, 25% and 26%, had no leakage occurred. Although the temperature field distribution was more uniform after molding, and has good hydrophobicity, the heat storage rate slows down. The thermal conductivities of the composite materials were respectively 2.7 ~ 3.7 times, 2.7 ~ 4.5 times, 2.7 ~ 4.4 times and 1.7 ~ 2.4 times than the corresponding pure organic acids. When the pressure changed from 1MPa to 11MPa, the resistivity of the composite materials decreased by 75.9%, 76.5%, 72.2% and 74.0%, respectively. The fitting of the change curve of the resistivity of the material showed a high correlation between them. It shows that the prepared composite phase change material has good hydrophobicity, thermal and electrical conductivity.