Abstract: Binary fatty acid(BFA)/SiO₂ phase change humidity storage composite materials were prepared by sol-gel method, which have phase change thermal control performance, humidity storage humidity control performance and can meet the compatibility with inorganic materials. The influence regulations of solution pH value, ultrasonic wave power, deionized water amount, absolute alcohol amount and BFA amount on structure of BFA/SiO₂ phase change humidity storage composite materials were studied. The chimeric mechanism of BFA/SiO₂ phase change humidity storage composite materials were analyzed by FTIR. The structure parameters and thermal-humidity performance in optimization performance forecast model of BFA/SiO₂ phase change humidity storage composite materials were studied by RBF neural network. The results show that the interaction between BFA and SiO₂ is only physical chimeric in BFA/SiO₂ phase change humidity storage composite materials. The preparation process parameters of BFA/SiO₂ phase change humidity storage composite materials with optimal thermal-humidity performance:solution pH value is 3.64, ultrasonic wave power is 120 W, deionized water amount is 1.45 mol, absolute alcohol amount is 0.78 mol and BFA amount is 0.079 mol. Predicted results:moisture capacity in 30% relative humidity(RH)~90%RH is 0.1676 g/g, phase change enthalpy is 41.89 J/g; Test results:moisture capacity in 30%RH~90%RH is 0.1653 g/g, phase change enthalpy is 41.22 J/g.