In order to realize the temperature regulation of phase change materials and solve the problem of leakage in practical applications, binary organic eutectic phase change materials (EPCM) were prepared by melting blending method using capric acid and methyl palmitate as raw materials, citric acid (CA) and carboxylated cellulose nanofiber dispersion (CNF) were used as raw materials, double cross-linked CA-Fe3+-CNF-Fe2O3 aerogels were prepared by sol-gel method, and finally EPCM was loaded with double cross-linked CA-Fe3+-CNF-Fe2O3 aerogels as carriers. Composite stereotyped phase change material (CA-PCM) was prepared, the eutectic points of capric acid and methyl palmitate were determined by step cooling curve, binary phase diagram and DSC, the influence of the mass fraction of CA (based on the total mass of CA and CNF, the same below) on its micromorphology was investigated based on SEM characterization, and EPCM, aerogel and CA-PCM were characterized and tested by FTIR, XRD, DSC, TGA, etc., and CA-PCM was used as the insulation material. Test its thermal buffering performance in building models. The results show that m(capric)∶m(methyl palmitate)=61∶39 is the actual eutectic point of capric acid and methyl palmitate, and the eutectic system (EPCM1) is formed by physical mixing, and the phase transition temperature is 24.3 °C and the enthalpy of phase change is 172.4 J/g. The aerogel prepared with 1% CA-Fe3+-CNF/Fe2O3 with 1% CA mass fraction was more and more uniform, and the morphology was more regular. The 1% CA-Fe3+-CNF/Fe2O3 aerogel was loaded with EPCM1 as the skeleton, the loading rate reached 85.57%, the phase transition temperature of the prepared 1% CA-PCM was 24.7 °C, the enthalpy value was 125.2 J/g, and the phase change temperature and enthalpy value did not change significantly after 100 cold and hot cycles. Compared with the foam model using plastic foam, the heating time of the PCM model using 1% CA-PCM as the building insulation material was increased by 51.3% and the cooling time was extended by 43.5%.