The problem of leakage identification for confidential database is a small-scaled pirate identification problem.After analyzing current solutions and their drawbacks,the author proposes a leakage identification and quantitative evaluation scheme for confidential databases,which is based on a compound database watermark technique.The principle of the novel database watermark technique and the watermark generation and detection algorithms are presented in the paper.By embedding a compound watermark in the data and applying a data watermarking and distribution protocol,the confidential database is bound to the identities of its owner and the user,so the interests of both parties can be fairly protected in the leakage identification process.Probabilistic analyses are adopted to provide a quantitative evaluation of the identification result.Experiments on the algorithms show that the proposed scheme is efficient and effective,and it is highly qualified for real world applications.