Disclosed is a method and apparatus for adjusting a playing speed of a video. The method for adjusting a playing speed of a video includes: after detecting a playing speed adjustment instruction of a target video, determining a target playing speed corresponding to the playing speed adjustment instruction; determining an initial frame rate of the target video, and taking the product of the initial frame rate and the target playing speed as a target parameter of the target video; processing the target video based on a preset frame number adjustment rule corresponding to a target comparison relationship; and adjusting timestamps of video frames contained in the processed target video, based on the preset target frame rate, so that the adjusted target video is played in the preset target frame rate. By applying the present solution, the adjusted target video can be played in the preset target frame rate, thus improving the display quality of the video whose playing speed has been adjusted, and improving the user experience.