An intra prediction method and device and a computer-readable storage medium, the method comprising: configuring actual angle modes indicated by relative angle indices, wherein the relative angle indices are successively represented within a prediction direction range corresponding to a preset width and height relationship; starting from a starting angle, using a corresponding actual angle mode after sampling preset angle sample points, said starting angle being determined according to the width and height relationship of processing blocks and the prediction direction range corresponding to the preset width and height relationship, and actual angles having a one-to-one correspondence with the actual angle modes.