At present, intelligent temperature-regulating fabrics have some problems, such as narrow temperature range, high price, and insufficient stability. In order to solve the problems, the low temperature phase change materials of capric acid/polymethyl methacrylate (CA/PMMA) and capric acid/polyvinyl alcohol (CA/PVA) were prepared by physical blending. A differential scanning calorimetry, a thermal conductivity tester, a fourier infrared spectrometer, and a synchronous thermogravimetric analyzer were used to characterize the thermal storage performance, thermal conductivity, chemical structure, and thermal stability of phase change materials. The results show that the CA/PVA low-temperature phase change material with 80% CA content has good comprehensive properties, with a phase change temperature of 29.69 ℃, a phase change latent heat of 325.40 J/g, and a thermal conductivity of 0.815 4 W/(m·K). The addition of PVA and PMMA promotes the interfacial compatibility of CA-based phase change materials, which makes the phase change materials have more defects and interfacial gaps, and the heat transfer efficiency is faster, which effectively improves the thermal conductivity. The coating of PVA and PMMA delays the migration of heat and oxygen from the combustion interface to the inside of the material, which plays a role in heat insulation and improved the thermal stability of the phase change material.