To develop a green solvent for chitin dissolution, the most fundamental aspects of its mechanism must be elucidated. In this work, an aqueous KOH/urea solution was utilized for the rapid dissolution of alpha-chitin without performing freeze-thaw cycles. It was found that the mechanism of alpha-chitin dissolution involved not only the fast expansion of its crystalline regions and hierarchical structure but also direct and strong interactions between K+ ions and chitin carbonyl oxygens. The relatively high flexibility and deformability of the K+ hydration shells allowed fast exchange between water molecules and carbonyl oxygens, which induced the cleavage of strong inter- and intramolecular hydrogen bonds, resulting in the rapid swelling and destruction of the chitin crystal and dissolution of alpha-chitin. Moreover, the additional urea mitigated the hydrophobicity of chitin chains, which prevented self-aggregation and increased the mobility of chitin chains. The described alpha-chitin dissolution mechanism can help achieve a better understanding of biomacromolecule dissolution.