A method for reducing computational complexity of video compression standard is provided, and it includes an intra 4×4 macroblock (I4MB) search algorithm, an intra 16×16 macroblock (I16MB) search algorithm and a chroma search algorithm. The I4MB search algorithm and I16MB search algorithm accelerate the prediction process of the luma macroblock, and the chroma search algorithm accelerates the prediction process of chroma macroblock. The above algorithms can greatly reduce the computation of prediction mode of video compression standard.