The present invention relates to a method for isolating a fraction having anti-inflammatory or osteoarthritis-inhibiting effects by removing impurities and washing oyster shells, which are produced during a process of producing oysters, drying same, forming a powder from the oyster shells, and adding anhydrous citric acid to same for a reaction, obtaining a reaction product, and isolating a supernatant, which is obtained by centrifugally separating the reaction product, by means of ultrafiltration. By adding the anhydrous citric acid to the oyster shell chips for the reaction at a relatively low temperature, the present invention provides superior advantages, such as significantly reducing energy costs and isolating the fraction having the anti-inflammatory or osteoarthritis inhibiting effects through a simple method.