A crane counterweight block alignment detection and control method, a crane counterweight block alignment detection and control device, and a crane. The crane counterweight block alignment detection and control method comprise: a counterweight block being provided with mounting holes for matching with positioning pins on a crane, detecting the center position of the counterweight block, and calculating the relative offset between the center position and the position of the positioning pins; detecting the relative positions of the mounting holes in the counterweight block and the positioning pins, and calculating, according to the positions, a relative rotation angle of the counterweight block for aligning the mounting holes with the positioning pins; and controlling, according to the relative offset and relative rotation angle, the movement of the counterweight block to enable the mounting holes in the counterweight block to be aligned with and installed onto the positioning pins.