A method and an apparatus for binarizing an intra prediction mode are provided. The method includes: acquiring an intra prediction mode of a luma component; if the intra prediction mode of the luma component is one kind of prediction mode in M, modifying a value of a serial number of a prediction mode Luma Angle of a chroma component to I; sequencing all prediction modes of the chroma component according to a preset rule; and performing binarization on the modified Luma Angle, and sending the binarized Luma Angle to a decoding end. A method for coding an intra prediction mode and a method and an apparatus for decoding an intra prediction mode are further provided. According to the present invention, coding efficiency is improved.