Abstract: In this paper, cellulose diacetate (CDA) was used as the skeleton material, and polyethylene glycol (PEG) as the phase change material to prepare PEG/CDA membrane composite cooling material by solvent blending and membrane casting method. Effects of membrane casting thickness, drying conditions and casting solution compositions on the physicochemical properties and cooling performance of PEG/CDA membrane composite cooling material were studied. The optimal preparation procedure of PEG/CDA membrane composite cooling material was as follows: 1.6 g of PEG₁₅₀₀ and 1.0 g of CDA were dissolved in 7.4 g of acetone solvent, and then the casting solution was obtained by stirring and refluxing in a water bath at 75 ℃ for 6 h. A membrane casting instrument was used to spread the casting solution into a 400 μm eiquid film on a clean glass plate, which then dried in a drying oven at room temperature for 12 h to obtain PEG₁₅₀₀/CDA membrane composite cooling material. Finally, the obtained membrane composite cooling material was cut into 160 mm × 16 mm strips, and then folded to form cooling elements. The cooling element could stably reduce the temperature of the mainstream smoke of heated tobacco products from 67 ℃ to 42 ℃ and the temperature of the tipping paper from 59 ℃ to 50 ℃, showing excellent use safety and good industrial application prospects. In PEG₁₅₀₀/CDA membrane composite cooling material, PEG₁₅₀₀ is uniformly loaded in the skeleton network structure formed by CDA. When the heated tobacco product is smoked, the PEG₁₅₀₀ crystals loaded in the CDA network structure will absorb heat by phase change, but the CDA network structure restricts the thermal motion of PEG₁₅₀₀ within a limited space, so that PEG₁₅₀₀ will not seep out of the network structure, showing the characteristics of solid-solid phase change under macroscopic conditions.