The embodiment of the invention provides a keyword extraction method and device based on graph and word and sentence collaboration. The method comprises the following steps of: based on candidate words and sentences obtained from a text of a to-be-extracted keyword, calculating the diffusivity corresponding to each two candidate words; calculating a first weight of an edge between every two candidate words in the undirected weighted graph based on the diffusivity, calculating a first index of each candidate word based on the first weight; calculating a second weight of an edge between every two sentences in the directed weighted graph, calculating a second index of each sentence based on the second weight, and obtaining a first index vector of the sentence based on a second index of the sentence, constructing a second index vector of each candidate word containing a fifth index of the candidate word based on the first index of each candidate word and the obtained first index vector, and extracting a keyword in the text based on a size sequence of the fifth indexes in the second index vector. According to the embodiment of the invention, the accuracy of extracting the keywords in the text can be improved.