The preparation process of three common nanocomposite phase change materials (NCPCMs) was studied by using the single-factor test method, and the influences of drying treatment, additives, ultrasonic power and time, base liquid volume and particle concentration on the stability of NCPCMs were analyzed. The results are as follows: (1) Drying treatment had the most significant effect on the stability of ZnO NCPCMs. Additive treatment has the most significant effect on the stability of Al2O3, and the improvement degree is about 9 times of CuO and 2 times of ZnO. (2) The ultrasonic power treatment method has the most significant effect on the stability of Al2O3 NCPCMs. For the sample with the worst preparation effect, the relative absorbance of the uniformly dispersed Al2O3 NCPCMs increased by 20.30%. (3) The stability of ZnO NCPCMs was significantly affected by ultrasonic time treatment and base liquid volume. Under the two preparation conditions, the relative absorbance of the uniformly dispersed ZnO NCPCMs increased by 65.67% and 38.24%, respectively, relative to the worst-performing samples. (4) The particle concentration factor has the most significant effect on the stability of CuO NCPCMs. At the same time, the optimal preparation scheme of NCPCMs was obtained. (C) 2019 Elsevier Ltd. All rights reserved.