A method for evaluating quality of video streams includes: obtaining video streams; obtain coding information of video frames in the video stream; evaluating the single frame quality according to the coding information of the video frames; and evaluating the sequence quality according to the single frame quality evaluation result. An apparatus and a system for evaluating quality are also provided. Thus, the quality of video data packets transmitted in a channel can be predicted accurately, and the single frame quality evaluation result of the video frames can be obtained immediately.