Abstract: Tetradecane nanocomposite phase change materials with mass fractions of 1%, 2%, 3%, 4%, and 5% were prepared using tetradecane as a base fluid, and nanoparticles Al₂O₃, CuO, MgO, and multi-walled carbon nanotubes (MWCNT) as additives, respectively. The morphology structure characterization and thermophysical properties were studied. The results showed that the addition of nanoparticles caused little change in the phase change temperature, and the latent heat values were reduced by 0.66% to 14.43%; thermal conductivity was significantly enhanced and increased with the increase in the mass fraction of nanoparticles; decomposition of the nanocomposite phase change materials occurred above 50 ℃, which was higher than the range of application; phase change time of the nanocomposite phase change materials was significantly shortened compared with that of pure tetradecane. The optimal nanoparticle was MWCNT with an optimal mass fraction of 3%, a thermal conductivity of 0.189 7 W/(m·K), and a latent heat value of 199.7 J/g, which can be used as a potential phase-change cooling storage material.