In this study, the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition, the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter, respectively. According to the analysis of main influencial factors of the property of CPCM, the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place, and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance, the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides, the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result, a desirable temperature-adjustable function appeared.