Aiming at the problem of accurate measurement of privacy leakage in social networks，especially when attackers has attack background knowledge，while privacy leakage is affected by many factors，a privacy leakage metrics method considering background knowledge should be considered comprehensively. A multi⁃dimensional analysis model for personal privacy leakage is proposed in this paper. Influencing factors of privacy leakage can be analyzed comprehensively. The greater influencing factor is deduced through calculation of leakage index. A method of classification and quantification of background knowledge is proposed，which can distinguish key background knowledge and non key background knowledge. On this basis，an information entropy model and a comprehensive measurement method of privacy leakage are proposed to solve the problem of measuring privacy leakage accurately. The proposed model and background knowledge quantification method can provide a favorable support for the quantitative research on the impact of attack background knowledge. Experimental verification and analysis results show that the measurement model is feasible and effective.

Keywords： social network ; background knowledge ; privacy disclosure ; privacy attack ; leakage metrics ; information entropy ; leakage risk analysis