This paper analyses how much Storage and Release Program for Price Stabilization (hereafter, 'The program') using Agricultural Price Stabilization Fund had changed the social welfare by computing the changes in producer's surplus, in consumer's surplus, and in governmental surplus for red pepper, garlic and onions from 1978 to 2003. This paper considers both public storage of domestic products and state trades in computing the change in social welfare. For the analysis is used Kooten and Schmitz(1985) model modified for public buffer stock. The Program had increased consumer's surplus and governmental surplus more than decreased the producer's surplus so that the Program increased social welfare by sacrificing producer's surplus. During the period, The Program hand increased social welfare 371 billion won ~ 385 billion won with red pepper, 307 billion won ~ 343 billion won with garlic, and 179 billion won ~ 186 billion won witoh onions. The total increase of social welfare by the three products were up to between 893 billion won and 914 billion won during the period.