Anthracnose of papaya is a latent infection mechanism. Papaya, being infected by anthracnose, will incure the disease at the post mature stage in retailing, thereby affecting the quality. The main reasons for the infection are that papayas' untrition provides what anthracnose needs, which result in spots, rolling and carbonization. Then they will lose commereial value. The aim of this study is to lengthen the shelf life of papayas in Taiwan by estimating Biological Protection. The method is considered in two ways. One is the cost that occurs from anthracnose. Another is the prospective benefit of adopint biological protection. The results will porvide references to the technological research institule.