According to the properties of the interaction between the molecules of antifreeze protein and the ice crystal surface in the solution of antifreeze protein,a model on the interaction between the molecules of antifreeze protein and the ice crystal surface is proposed. The theoretical relations between the antifreeze activity and concentration of antifreeze protein are given by using of the relation between the saturation fraction and antifreeze activity.The theoretical curves of relations between the antifreeze activity and consentration of antifreeze proteins are given by using of these relations.These theoretical results are consistent with experimental datum.Furthermore,the properties of interaction between the molecules of antifreeze protein and the ice crystal surface are discussed.