To improve the controllability of the fabrication of carbon aerogels, the effects of the concentration of the reactant (RF%) on the structural properties of organic resorcinol - formaldehyde (RF) gel and the effects of the carbonization temperature on nano-structure of carbon aerogels were discussed. The concentration of the reaction was turned from 5%,10%,20%,30%,40%,50%, 55% and 60% to prepare the samples. The RF aerogels were carbonized at temperature of 700°C, 900°C and 1050°C. The shrinkage and nitrogen gas adsorption were measured. Experimental results showed that the structural stability of the organic RF aerogel can be improved by decreasing the shrink in drying process and increasing the condensation of reactant in the starting solution to a certain value, such as 55%. The ordered pore size distribution of carbon aerogels with less structure defects is able to be produced through the effective particle fusing at the carbonization temperature as high as 1050°C.