The present invention relates to method for image visual effect improvement of video encoding and decoding. The method at an encoder comprises enhancement process of image boundary information, adaptive brightness transformation process, and adaptive enhancement process of chrominance information. The method at a decoder comprises adaptive enhancement of boundary information based on the block statistical characteristic, adaptive brightness transformation process, and adaptive enhancement process of the chrominance information. Based on characteristics of the image source at the encoder and the decoder, the present invention uses brightness space processing technology to eliminate blocking artifacts, enhance high frequency information and improve brightness information distribution, so as to improve brightness information of the image in one aspect, and uses the chroma space processing technology to enhance color effect of the image in the other aspect, and finally, the objective of improving visual effect of the image is achieved.