The invention relates to a language analysis of an extensible markup language security application, relating to a computer data processing technology field; The method includes: according to the content needing for signature and with encryption of the known safety strategy as well as the signature way, the corresponding position information of all path expression is ensured; according to the path expression, the data structure of finite state automata is correspondingly built with a character in the path expression used as of the state jumping condition of the automata; a message string of the safety strategy is applied by inputting orderly the finite state automata for matching and receiving XML message to safe process the needed position message; the XML message of the original serialization string format as well as the offset sequence of the position message are regarded as a analysis result, and inputted to a safety processing module of the XML safety application for safety processing. The invention can improve the entire performance of the XML safety application from the time and space consumption.