Biomass carbon aerogels with high specific surface area derived from sweet potato were prepared by freeze?drying and alkali activation processes. Sweet potato carbon aerogels (SPCA) and activated sweet potato carbon aerogels (ASPCA) with different morphologies and features were prepared by changing carbonization temperature and activation method. The prepared biomass carbon aerogels were characterized and analyzed by SEM, XRD, low temperature nitrogen absorption/desorption test and Raman spectroscopy. The results show that with the increasing of carbonization temperature, the pores increased, furthermore, alkali activation has a great promotion effect on the formation of pores on ASPCA. The prepared biomass carbon aerogel has good adsorption performance, and the maximum adsorption capacity for Rhodamine B (RdB), methyl orange (MO) and alizarin red (ARS) in deionized water is 202.2 mg/g, 83.6 mg/g and 160.2 mg/g, respectively.