The invention relates to a device and method for processing a turbine diaphragm thick lashing strip type hole by utilizing a linear cutting device, and relates to the device and method for processingthe turbine diaphragm thick lashing strip type hole. One surface of a bottom plate of the device is a hook face; the radian of the hook face is equal to the radian of a turbine diaphragm thick lashingstrip; an arc-shaped groove is formed in the hook face; the radian of the hook face, the radian of the arc-shaped groove and the radian of the turbine diaphragm thick lashing strip are equal; two positioning pin holes are formed in the arc-shaped groove; two positioning pins can be fixed onto the positioning pin holes in the arc-shaped groove in the way of being perpendicular to the tangential direction of the arc-shaped surface of the arc-shaped groove; a blanking hole is further formed in the arc-shaped groove; two bulge edges are formed on two sides of the arc-shaped groove; two ends of each pressing plate are pressed on the two bulge edges; the pressing plate can be fixed onto the two bulge edges through screws; positioning screw holes laterally penetrating through the bulge edges areformed in the outer side surfaces of the bulge edges; and positioning screws are arranged in the positioning screw holes, so that the turbine diaphragm thick lashing strip is fixed. The device and method provided by the invention are suitable for processing the turbine diaphragm thick lashing strip.