Abstract: Oct@PMMA microcapsules phase change materials were synthesized by the emulsion polymerization method, and the energy storage performance and thermal stability was improved by selecting PVP as dispersing agent and PETRA as cross-liking agent. The chemical and physical properties of the microcapsules were characterized by FT-IR, XRD, DSC and TG. The results showed that the thermal performance and yield were improved by PVP, increasing the stability and dispersibility of emulsion droplets, the enthalpy in phase transition was 105.6 J/g and the yield reached 98.01%, the thermal stability was enhanced by PETRA and the decomposition temperature was up to 175 ℃.