The invention discloses a preparation method of a carbamide resin phase change microcapsule, and belongs to the field of preparation of textile materials. The method is characterized by comprising thefollowing steps: dissolving n-octadecane and TDI in a cyclohexane solvent, so as to form a uniformly mixed oil phase system; weighing an emulgator and OP-10, feeding the emulgator and OP-10 into a flask containing distilled water, and stirring, so as to form a uniformly mixed aqueous phase system; pouring the oil phase into an aqueous phase flask, and stirring with a homogenizer, so as to form uniform O/W emulsion; transferring the emulsion into a three-mouth flask, and reducing the rotate speed; uniformly mixing DETA and distilled water, dropwise adding the DETA and distilled water into theemulsion at a constant speed, and slowly performing temperature reaction after dropwise adding is accomplished, so as to obtain microcapsule suspension; performing suction filtration on an obtained product, washing the obtained product through distilled water and alcohol, performing suction filtration, and finally drying an obtained filter cake in a vacuum drying oven, so as to obtain a n-octadecane/carbamide resin phase change microcapsule. The carbamide resin/n-octadecane phase change microcapsule has the advantages that the enthalpy value of the microcapsule is 95.81 J/g, the packaging efficiency is 92.13 percent, and the thermal stability of the microcapsule taking carbamide resin as a wall material is excellent.