The invention provides a speed change software implementation method and device. The speed change software implementation method comprises the steps that a time function used in the current process of software to conduct speed change is determined; in the current process, the determined time function is used for calculating the time difference of the originally-set playing time of a current audio frame and/or video frame and the originally-set playing time of a next audio frame and/or video frame; the time difference is adjusted according to input speed change parameters; the next audio frame and/or video frame is played after the time of the adjusted time difference with the actual playing beginning time of the current audio frame and/or video frame as the starting point. By means of the speed change software implementation method and device, the effects that the safety of the speed change software achieving the speed change function is improved, and the system burden is relieved are achieved.