A method and a device for creating a pattern matching state machine are provided. The method includes: obtaining a predefined keyword set; generating a Goto function according to the keyword set; constructing a Failure function according to the generated Goto function, and setting that an acceptable input set of the Failure state of each state is not a subset of an acceptable input set of the state, where the acceptable input set of the state indicates that when any symbol within the symbol set is input in the state, the Goto function of the state does not fail; and generating an Output function according to the Goto function and the Failure function.