Starch based carbon aerogel has attracted significant attention due to the wide source, environmental friendliness and low price of raw materials. Here, starch based carbon aerogel was fabricated by graft reaction and cross-linking reaction of starch. The network structure of starch hydrogel was optimized through graft and cross-linking reaction. After freeze drying and high temperature carbonization, the obtained carbon aerogel that carbonized at 800 °C showed a specific surface area of 1508 m2·g−1 without activation which is far higher than that of other unactivated carbon aerogels. The starch based carbon aerogel carbonized at 800 °C exhibited superior methylene blue adsorption ability with a maximum adsorption capacity of 963.5 mg·g−1 as a result of its rich surface functional groups, high specific surface area, and reasonable pore size distribution. Furthermore, the carbon aerogel carbonized at 700 °C exhibited excellent electrochemical performance with a specific capacitance of 180.1 F·g−1 at a current density of 1 A·g−1as electrode materials for supercapacitors. Overall, this work provides a new method to prepare high performance starch based carbon aerogel.