Abstract: This article proposes a friend matching scheme based on private intersection sum. The solution is designed to ensure fairness in the friend matching process, data security, and the accuracy of the matching function through private intersection sum technology. In this scheme, elements of both data sets have corresponding values. The data set elements are processed into fixed lengths through the hash function, and compared with the idea of Diffie-Hellman key exchange protocol to obtain the cardinality of the set intersection, thereby eliminating the asymmetry of the corresponding values of the data set elements and ensuring the intersection sum computational fairness. At the same time, the homomorphic encryption algorithm is used to process the corresponding values of the elements, achieving privacy protection for the values. This enables the solution to effectively achieve the accuracy and security of the dating matching function while protecting user privacy.