The embodiment of the invention discloses a method and device for extracting a keyword. The method comprises the following steps: acquiring a participle set of a to-be-treated text according to a preset rule, wherein the participle set at least contains first to Nth participles; confirming a webpage PR value of a ith participle in the participle set; confirming a coding distance between every two participles in the participle set; acquiring a first coding distance set which contains the coding distances between the ith participle and the other participles except for the ith participle; confirming the relevancy of the ith participle according to the first coding distance set and an ith threshold value corresponding to the ith participle; confirming the criticality of the ith participle according to the PR value of the ith participle and the relevancy of the ith participle; and confirming the keyword of the to-be-treated text according to the criticality of the first to Nth participles. According to the technical scheme provided by the embodiment of the invention, the problem of inaccurate extraction for the keyword in low occurrence frequency in the keyword extracting process can be solved.