To develop a new process for producing chitin from crayfish shell， demineralization and deproteinization of crayfish shell by electrolyzed water （EW） were studied， and the physicochemical properties and structure of chitin extracted were characterized. The results showed that after crayfish shell powder （CSP） was treated individually with acidic electrolyzed water （AEW） and basic electrolyzed water （BEW） prepared by 2% NaCl for 6 h， the mineral and protein removal rates were 99.59% and 91.31%， respectively. After CSP was continuously treated by the combination of AEW and BEW for 9 h， the ash and protein contents of chitin prepared were 0.86% and 1.31%， respectively. AEW also had good decolorizing effect. Compared with the traditional inorganic acid-base method， the chitin produced by the EW treatment process had lower intrinsic viscosity （368 mL/g）， molecular weight （85 ku） and degree of deacetylation （12.88%）. The results of thermogravimetric analysis and differential thermal analysis， scanning electron microscopy， Fourier transform infrared spectroscopy and X-ray diffraction showed that both chitins exhibited a network-like porous structure and all were α-chitin. The degradation temperature of them were 382 ℃ and 389 ℃， respectively， and the crystallinity index were 82.48% and 78.82%， respectively. Therefore， EW treatment process has the potential to be a novel method for producing chitin from crayfish shell.