Abstract: A face annotation method and a face annotation system are provided. The face annotation method is adapted for a current owner to annotate contacts in online social networks. The face annotation method comprising: providing a pyramid database access control module which consists of a plurality of pyramid database units and performs a first batch of access control procedure and a non-first batch of access control procedure, wherein the pyramid database unit is constructed according to social relationship information; providing a multiple-kernel learning face recognition module implemented through the use of a MKL classifier unit which uses a MKL algorithm to achieve a face identification; and if the MKL-FR model is not able to identify query faces, providing a multiple-kernel learning face recognition fusion module to perform a collaborative face recognition strategy by utilizing a user who features a highest priority rule within a collaborative face recognition framework.