In this study,both α-chitin powders and nanofibers were successfully dissolved in NaOH solutions at low temperatures.Elemental analysis confirmed that this NaOH-freezing treatment didnt cause deacetylation of chitin.After heating and neutralizing with water,chitin hydrogels could be prepared.X-ray diffraction and FE-SEM data demonstrated that these two hydrogels formed typical regenerated micro-porous structures with low crystallinity which was caused by dissolution process.Based on this result,cold ethanol was used for α-chitin nanofibers during the initial stages of neutralization which effectively prevented the dissolution and decrease in crystallinity,and was even able to preserve the continuous network structure of original nanofiber.This gelation behavior seems to be attributed to interdigitation and aggregation between neighboring nanofibers in cold alkali solution leading to the shrinkage of hydrogel.In general,by avoiding dissolution process,high crystalline hydrogel based on α-chitin nanofibers was prepared by a simple NaOH treatment without use of any other chemical solvents or cross-linking agents.We expect this new type of hydrogel could be promoted to wide applications and researches as novel green nanomaterials.