Method and system for provide related keyword

PURPOSE: A related key word providing method and system thereof are provided to improve the convenience of a searching method in a portal site by recommending key words related to an input key word. CONSTITUTION: A related key word providing unit(220) requests a key word related to the selected key word or an input key word. A related key word extraction unit(230) extracts the related key word corresponding to the request of the related key word providing unit. A list creation unit(240) creates a category related to the extracted key word and transmits the related key word providing unit. A storage unit(260) stores the input key word and the selected related key word. A history creation unit(270) transmits the related key word to a providing unit by creating the key word stored in the storage unit.