Abstract: With silane coupling agent modified SiO₂ as wall material and decanoic acid (DA)-palmitic acid (PA) as call material, the DA-PA@modified SiO₂ temperature and humidity control composites were prepared by sol-gel method with ultrasonic wave-assisted. The effects of the content of silane coupling agent, ultrasonic wave power, ultrasonic wave time and ultrasonic wave temperature on the particle size of the DA-PA@modified SiO₂ temperature and humidity control composites and related properties were investigated. The results show that the particle size and its distribution of the DA-PA@modified SiO₂ temperature and humidity control composites can be significantly reduced using sol-gel method with ultrasonic wave-assisted. With the content of silane coupling agent of 4.0 g, ultrasonic wave power of 120 W, ultrasonic wave time of 100 min and ultrasonic wave temperature of 60℃, the DA-PA@modified SiO₂ temperature and humidity control composites has small diameter and narrow particle size distribution, such as d₉₀=87.36 nm, d₅₀=63.34 nm, d₁₀=44.02 nm and d₉₀-d₁₀=43.34 nm. Its equilibrium moisture content in the relative humidity of 40.0%-65.0% is 0.1864-0.2379 g/g, phase change temperature is 20.23-23.59℃, phase change latent heat is 40.91-46.72 J/g, and the stability performance is good.