To utilize shellfish by-products effectively, chitin, chitosan, and microcrystalline chitin were prepared from 6 kinds of crustacean shells(Antarctic krill, Euphausia superba; Red snow crab, Chinonecetes japonicus: Daelongsuyum shrimp, Solenocera prominentis: Lobster, Linuparus trigonus: Gasibal shrimp, Nephrops thomsoni: Blue crab, Portunus trituberculatus) and their functional properties were studied. Apparent volume(AV), settling volume(SV), water binding capacity(WBC), and fat binding capacity(FBC) of various chitins, chitosans, and microcrystalline chitins ranged from $3.1pm0.1ml/g;to;27.0pm0.2ml/g$ from $5.1pm0.1ml/g;to;45.0pm0.2ml/g,;from;318pm40g/100g;to;2,382pm12g/100g,;and;from;235pm20g/100g;to;2,169pm20g/100g$, respectively, and the krill chitin and chitosan had the highest AV, SV, WBC, and FBC of them. Chitins and chitosans did not produce emulsion but microcrystalline chitins showed emulsifying properties. Emulsifying capacity and stability of various microcrystalline chitins ranged from $18.2pm4.0\%;to;50.1pm2.5\%;and;from;15.2pm3.5\%;to;31.1pm1.0\%$, respectively. Dye binding capacity of microcrystalline chitins was higher than that of chitins or chitosans.