A method and a device for assessing video encoding quality. The method includes: acquiring a quantization parameter of a slice of a video frame and a quantity of bytes per pixel of the slice of the video frame of the video stream; determining complexity of content of the video according to the quantity of bytes per pixel of the slice of the video frame of the video stream; and predicting the video encoding quality according to the complexity of content of the video and the quantization parameter of the video. In the present invention, the complexity of content of the video is also considered in predicting the video encoding quality. Therefore, encoding quality predicted by a model that is obtained by considering the complexity of content of the video better satisfies subjective feelings of human eyes, thereby improving accuracy of prediction.