The embodiment of the invention discloses an updating method and an updating device of a sub-band search association table, a cell search method and a cell search device. The updating method of the sub-band search association table comprises the following steps: acquiring a central frequency point of a cell searched by a mobile terminal, bandwidth of the cell and public land mobile network PLMN information of the cell; calculating sub-band of the cell according to the central frequency point and the bandwidth; and adding information of a corresponding relation of the sub-band of the cell and the PLMN information of the cell into the sub-band search association table. The methods and the devices provided by the invention solve the technical problem that the cell search method in the prior art increases delay of cell search, reduces efficiency of searching an appropriate cell and seriously influences experience of users, optimize the existing cell search technology, and meet the increasing personalized and convenient cell search demands of people.