The invention provides a method for shearing and shrinking spent fuel-related components of a nuclear power plant. The method comprises the following steps: a first transferring step: transferring thespent fuel-related components from a spent fuel pool to a roll-over frame; a first roll-over step: driving the spent fuel-related components from a vertical direction to a horizontal direction by theroll-over frame; a second transferring step: transferring the rolled-over shear-related components to a shearing platform and fixing by a fixing fixture on the shearing platform; a shearing step: after shearing part of single rods one by one with a shearing tool, driving the spent fuel-related components to rotate at a preset angle by the fixing fixture, and shearing part of single rods one by one with the shearing tool; a second roll-over step: transferring the single rods out of the shearing platform, changing the single rods from a horizontal state to a vertical state under action of gravity; and a third transferring step: respectively transferring head parts of the single rods and the spent fuel-related components into corresponding storage containers. The method provided by the invention can shear according to actual situation of each single rod to avoid failing to shear the single rods and reduce safety hazards.