The invention relates to a multimedia technology, and provides a method and device for realizing a time shift function, so as to improve the accuracy of video contents searched by a time shift mode. The method is that: a network server re-performs fine slicing on N original slicing files including a time shift start position point before the time shift start position point according to an appointed target time length, and sends a plurality of acquired target slicing files to a time shift terminal; and the time shift terminal can perform time shift operation in the plurality of target slicing files according to a preset step length till a time shift start end point indicated by a user. Compared with the original slicing files, the target slicing files are shorter in time length, so that thetime shift terminal is positioned to the time shift start end point appointed by the user more easily during the time shift operation, and then the accuracy of the video contents searched by the timeshift terminal through the time shift mode can be effectively improved, and a skip phenomenon of the video contents in a time shift process is avoided.