Abstract: Low density polyethylene (LDPE)-paraffin-graphite composite shape stabilization phase change material (SSPCM) was prepared by melt blending method. Thermal energy storage sulphoaluminate cement-based composite mortar (TESCCM) was prepared by using sulphoaluminate cement as cementing material and SSPCM as latent heat storage material. The microstructures, heat storage capacity and thermal stability of SSPCM and TESCCM were analyzed by using SEM, laser scanning confocal microscope(LSCM), DSC and TGA. By testing the compressive and flexural strength of TESCCM, the influence of SSPCM content on the mechanical properties of TESCCM was analyzed, and the thermal regulating property of TESCCM was evaluated by the self-made thermal performance test chamber. The results show that LDPE can form a multi-layered network structure, which can realize the effective encapsulation of phase change paraffin. The latent heat value of the prepared SSPCM can reach 88.02 J/g, and SSPCM is well integrated with the cement matrix; TESCCM has the characteristics of good thermal stability, fast strength growth, high early strength and high tempering performance. Increased SSPCM content reduces the strength of TESCCM, but improves the toughness of TESCCM. The 1 d and 3 d compressive strength of TESCCM(the mass ratio of SSPCM to cement is 50%) were 5.58 MPa and 6.51 MPa, respectively, the ratio of its compressive strength and flexural strength at 28 d is 2.7.