The present invention discloses a method for switching video playback resolution, including: obtaining a strength of a current network signal as well as a frame rate of a currently-played video; based on the strength of the current network signal, switchable resolutions of the video, and the frame rate of the video, calculating switching time intervals of the switchable resolutions; based the strength of the current network signal, switching the resolution of the video by selecting an optimal switching time interval and the corresponding switchable resolution, and storing the optimal switching time interval and the corresponding switchable resolution in a time interval table which carries the strength of the corresponding network signal at each calculation of the switching time intervals. The present invention further discloses a system for switching video playback resolution and a television having the same.