The self-healable biomass aerogel is achieved by electrostatic interaction between the chitosan (CS) and itaconic acid (IA). Once the aerogel is cut apart, it can repair both its structure and mechanical performance within 30 s at room temperature via treatment of wetting. After self-healing for 100 s, it can even bear a weight which is almost 3300-fold heavier than the original weight of the aerogel itself. Display omitted •Disclosing a new strategy for the fabrication of self-healable aerogels.•Ultrafast self-healing capacity was achieved under the stimulus of water.•CSA aerogels display excellent recyclability.•Showing outstanding mechanical property before and after self-healing. Achieving self-healing capacity in porous materials is highly attractive, but still remains a huge challenge. Here we disclosed a new strategy for the fabrication of self-healable biomass aerogels, which is achieved by assembling the positively charged chitosan (CS) and negatively charged itaconic acid (IA) in aqueous solution, followed by a freeze-drying process. Due to relatively strong electrostatic interaction and unique morphology, the aerogel shows outstanding mechanical property even at very low apparent density. More importantly, it possesses ultrafast self-healing ability at room temperature. Once the aerogel is cut apart, it can repair both its structure integrity and mechanical performance within 30 s at room temperature via wetting one fractured surface. After self-healing, its compression strength is almost twice the value of the original one. In addition, the aerogel can be completely dissolved and reshaped, thus displaying excellent recyclability of the materials. Since both CS and IA are derived from natural resources, this work provides a promising solution to the fabrication of self-healable biomass aerogels with both high-performance and sustainability.