NOVELTY - Preparing core-shell structure composite phase change material involves: 1) dropping secondary butanol aluminum into de-ionized water, adding ethyl acetoacetate and aging to obtain alumina sol; 2) mixing ethanol and de-ionized water, adding coupling agent, mixing and adding aluminum-containing alloy powder; 3) heating obtained mixed solution, stirring, filtering, washing and drying to obtain surface modified aluminum-containing alloy powder; 4) adding powder obtained in the step 3) to the alumina sol in the step 1) and heating; and 5) drying the obtained gel and cooling.    USE - For preparing core-shell structure composite phase change material via coupling agent modified aluminum-containing alloy (claimed), where the material is useful in field of aerospace heat protection and radiating field of electronic component and for solar energy power generating.    ADVANTAGE - The process solves the problems that the shell thickness of the core-shell phase change material encapsulated by using the conventional sol-gel method is thin and the encapsulating efficiency is low; provides the features of thick coated shell layer, compact shell layer, smooth surface and no impurity; is simple process and has low cost and stable performance; can be used for industrial recovery, solar energy power generating, aerospace heat protection and radiating field of electronic component; is suitable for more rigorous use environment; and recycles the afterheat, solar energy generating electricity heat.    DETAILED DESCRIPTION - Preparing core-shell structure composite phase change material via coupling agent modified aluminum-containing alloy, involves following steps: 1) weighing sec-butyl aluminum, de-ionized water and ethyl acetoacetate with a mol ratio of 1:(40-120):(0.01-0.5), and then the secondary butanol aluminum by dropping into the de-ionized water at 85-95 degrees C water bath under the condition of stirring for 5-10 minutes, then adding ethyl acetoacetate at 85-95 degrees C of water bath condition for 2-4 hours, then placing and aging for 9-11 hours to obtain alumina sol; 2) weighing ethanol, de-ionized water, coupling agent and aluminum-containing alloy powder, where the weight ratio of the ethanol and de-ionized water is (9-99):1, the mass ratio of the coupling agent and the ethanol is 1:(50-300), and the mass ratio of the ethanol and the aluminum alloy powder is (10-3):1, mixing ethanol and de-ionized water, and then adding coupling agent, mixing them uniformly, adjusting the pH value of the solution to be 4-5, then adding aluminum-containing alloy powder, mixing them uniformly, and obtaining mixed solution, where the coupling agent is at least one gamma -glycidylpropyltrimethoxysilane (KH560), aminopropyltriethoxysilane (KH550), gamma -(methacryloxyl) propyltrimethoxysilane (KH570), NXT201, or NXT102; 3) heating the obtained mixed solution to 115-125 degrees C and stirring for 23-25 hours, then filtering, washing the obtained solid phase by ethanol, and then drying for 2-4 hours at 115-125 degrees C to obtain the surface modified aluminum-containing alloy powder; 4) adding the surface modified aluminum-containing alloy powder obtained in the step 3) to the alumina sol prepared in the step 1), heating to 55-65 degrees C and preserving this temperature for 2-5 hours to obtain gel, where the mass ratio of the aluminum-containing alloy powder in the surface modified aluminum alloy and the sec-butyl aluminum in the alumina sol is 1:(0.5-5); and 5) drying the gel obtained in the step 4) for 24-48 hours into an oven at 45-55 degrees C, then putting into a muffle furnace, raising the temperature to 1100-1300 degrees C at the heating speed of 10-15 degrees C/minute, keeping warm for 3-5 hours, and then cooling to room temperature in the furnace to obtain the core-shell structure composite phase change material.