Carbon aerogels were synthesized through a sol-gel process by polycondensation of phloroglucinol, resorcinol and formaldehyde, using salicylic acid, m-hydroxybenzoic acid, gallic acid, oxalic acid and succinic acid as the acid catalyst, respectively. The effects of reactants solution pH values on the gel time were studied, and the structure of carbon aerogels was characterized by X-ray diffraction and scanning electron microscopy. The specific surface area, pore size distribution and pore volume were measured by surface area analyzer. Electrochemical properties of carbon aerogels were measured by cyclic voltammetry and galvanostatic charge/discharge measurements. The results show that the gel time was the shortest and the specific surface area of carbon aerogel was the highest, up to 753 m(2) g(-1), and the specific capacitance was 97 F g(-1) at pH 1.58 in the presence of oxalic acid.