The invention provides a label lexicon updating method and device and an electronic device, which relate to the technical field of label updating. The method includes the steps of obtaining label search term input by a user; finding a search service log corresponding to the label search term; carrying out log analysis of search service logs to determine key indicators of labeled search terms; updating the tag lexicon based on key metrics. The invention can dynamically update the label lexicon so that the label lexicon can satisfy the search requirement.