Abstract: The ultra-low density resorcinol (R)-formaldehyde (F) aerogel and carbon aerogel were prepared via a sol-gel route, which density are 10 mg/cm³ and 20 mg/cm³, respectively. The microstructures and properties of the carbon areogel were investigated by using scanning electron microscope, transmission electron microscope, pore size distribution measurement, and so on. The ultra-low density products are some tortuous chains consisting of carbon nanospheres ranging from 10 to 15 nm. The carbon nanosphere consists of nanoparticles whose sizes are about several nanometers. The surface area of the low-density carbon aerogel is 1 783.7 m²/g. The hydrogen adsorption capacity of the ultra-low density carbon aerogel is 4.4% (mass fraction) at liquid nitrogen temperature under atmospheric pressure.