A prediction image generation method and apparatus using a single coding mode for all color components and image and video encoding and decoding methods and apparatuses using the same are provided. The prediction image generation apparatus includes: a spatial prediction image generation unit applying an identical prediction direction for each image component in an original image composed of at least two image components, and obtaining a spatial prediction image from a pixel spatially close to a pixel block of a predetermined size of a current frame; a temporal prediction image generation unit applying an identical block size, motion vector, and motion interpolation method for each image component in an original image composed of at least two image components, and obtaining a temporal prediction image by estimating motion in units of blocks of a predetermined size between a previous frame and a current frame of each of the image components; an encoding mode selection unit selecting an encoding mode by using the spatial prediction image and the temporal prediction image; and a single mode prediction image generation unit generating a prediction image by identically applying the encoding mode selected in the encoding mode selection unit to each component. By increasing the redundancy of information between prediction error signals of color components, the encoding efficiency can be enhanced in the method and apparatus.