In order to solve the leakage problem of hydrated salt phase change material (PCM) and explore a lower-cost and environmentally friendly carbon aerogel to encapsulate hydrated salt phase change material, KGM/ CNC carbon aerogel was successfully prepared by directional freezing-casting and high temperature carbonization using konjac glucomannan (KGM) and cellulose nanocrystal ( CNC) as raw materials. Konjac glucomannan / cellulose nanocrystal phase change material (KGM/ CNC PCM) was prepared by vacuum impregnation method using Na2 SO4 ·10H2O-Na2HPO4 ·12H2O eutectic salt (EHS) with 0. 2% (mass fraction) nano-carbon particles as phase change matrix. The structure composition of KGM/ CNC carbon aerogel was analyzed by SEM, EDS, XRD, Raman, FTIR, XPS and BET. The thermal properties of KGM/ CNC PCM were studied by DSC and TG. The results show that KGM/ CNC carbon aerogel has good compatibility with EHS. KGM/ CNC PCM could load 98. 3% ( mass fraction) EHS, and the melting enthalpy and crystallization enthalpy could reach 273. 3 and 239. 1 J·g - 1 , respectively. After 5 000 solid-liquid cycles, the melting enthalpy and crystallization enthalpy decrease by 1. 4% and 2. 8% , respectively. This paper solves the problem of poor cycle stability of hydrated salt phase change material, which is helpful to further promote the application of hydrated salt phase change energy storage material.