Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-Glucosamine (deacetylated unit) and N-acetyl D-Glucosamine (acetylated unit). It is made by treating shrimp and other crustacean shells with the alkali, sodium hydroxide. Chitosan has some therapeutic activities like lowering cholesterol, antiulcer, and wound healing and antimicrobial activity. Recently electrospinnanofibers based on chitosan have been widely researched. Chitosan have many physicochemical properties like colorless, white hard, inelastic, nitrogenous polysaccharide. It chelate with many transitional metal ion .The degree of substitution of hydroxyl and amino group also influence the mechanical and biological properties of chitosan samples. In recent year a lots of biological, medical and commercial applicability are being used. The amino group in chitosan has a pKavalue of ~6.5, leads to a protonation in acidic to neutral solution with a charge density dependent on pH. This makes chitosan water-soluble. Though the drug delivery by chitosan is not approved by FDA, purified form are available for biomedical application. This review gives clear information about introduction properties processing and applications of chitosan.