In this study, we examined whether organic calcium can replace the inorganic calcium. We investigated the quality characteristics of egg produced from laying hens with non-supplemented diets or diets supplemented with organic calcium on chitosan oligosaccharide. We are made of organic-calcium on substrate of chitosan oligosaccharide. Organic calcium or non-organic calcium were mixed normal laying hen diet. Laying hens were fed diet for 45 days containing powdered chitosan oligosaccharide-Ca, Inorganic calcium or normal feedstuff. Through the whole period of experiment, organic calcium group significantly increase the egg colors, egg shell thicken compared to normal (p<0.05). And, egg weights, edible weight and egg heights were no significant difference. Each effectiveness are different from organic-calcium concentration. Overall, It was investigated that organic calcium had equal or more effects compared with inorganic calcium or normal diet. These results suggest that organic calcium could be used as substitute for inorganic calcium as well as the supplement of laying hens diets to produce functional eggs.