In this paper, we use the ammonia borane (AB) as raw materials, thiourea as vesicant to synthesize the three-dimensional boron nitride foam by one-step, template-free, high-temperature thermal decomposition method.The property of high surface area, appropriate pore size distribution, high yield, low apparent density,large lamellar structure, thin lamellar thickness, which make it a possible candidate for catalyst carrier.Here we use the ultraviolet irradiation method to prepare the Ag/3D BN catalyst, which exhibits good catalyst performance in catalytic oxidation of volatile organic compounds (methanol), such as the high catalytic activity with the light-off temperature (T50) as low as 50℃, the temperature of T95 only 110℃, the high thermal stability with reactivity maintained dozens of hours without significant change, which shows obvious advantages than Ag/γ-Al2O3 catalysts.Additionally, this 3D BN product shows great potentials applications in the field of catalysts for environmental governance and purification.