A chroma prediction method includes: obtaining luma information and chroma information of a to-be-processed image block, first processing information, and second processing information, where the first processing information indicates a downsampling processing manner used for a luma component of the to-be-processed image block, and the second processing information indicates a downsampling processing manner used for a chroma component of the to-be-processed image block; reconstructing a transient luma block of the to-be-processed image block based on the luma information of the to-be-processed image block, where a resolution of the transient luma block is determined by using a sampling format of the to-be-processed image block and the first processing information; and obtaining a prediction block of a transient chroma block of the to-be-processed image block based on the resolution of the transient luma block, the sampling format of the to-be-processed image block, and the second processing information.