The development of 3D nitrogen doped graphene aerogels (N-GAs) have attracted great attention due to the excellent performance in electrochemical applications and energy storage. Herein, we present a solid supported method for synthesis of rich porous N-GAs with high specific surface area using urea and KOH as supporting followed by drying at ambient pressure and temperature. The urea and KOH are introduced into the gap of graphene aerogels (GAs) through simple impregnating to effectively prevent the GAs from agglomerating. Consequently, the urea and KOH endow the 3D N-GAs with porous characteristic, high nitrogen content, large specific surface area and good monolith macromorphology. The N-GAs are tested as a binder free electrode for supercapacitor. A specific capacitance as high as 175 F g(-1) at 0.5 A g(-1) is obtained and an acceptable stability with 87% of initial capacity is retained after 5000 cyclic tests.