Abstract: In this paper,paraffin was vacuum-impregnated in expanded vermiculite as the inner phase,and acrylamide aqueous solution was used as the outer phase to prepare an oil-in-water emulsion. The initiator polymerized the outer phase to obtain shape-stable composite phase-change heat storage particles. The test results show that when the emulsifier is 6% of the paraffin mass and the expanded vermiculite is 2% of the paraffin mass,the melting enthalpy value is 128.79 J/g,and the paraffin coating rate is 72.80%. The shape of the composite particles is regular in the surface. The particles are spherical and uniform in size. After 100 cycles,the melting enthalpy only decreases by 2.18%. The composite particles have good thermal stability below 470 ℃. The secondary encapsulation of paraffin by expanded vermiculite and polyacrylamide effectively improves the anti-leakage capability of the composite system,and has reliable energy storage and temperature regulation performance.