The invention discloses an installation method of a blade. The installation method of the blade belongs to the technical field of cutter processing and preparing, and is characterized by comprising the following steps of a, placing a cutter body on a cutter clamping device; b, downwards moving an inserting plate of a cutter body alignment device, inserting the inserting plate into an inserting slot of the cutter body, rotating a stepping motor to drive the inserting plate to rotate, enabling the inserting slot of the cutter body to align at a placement position of a blade of a next process, upwards moving the inserting plate, and separating the inserting plate from the inserting slot; and c, pushing the blade out through a blade pushing air cylinder of a blade placement device, rotating the air cylinder to drive a double-shaft air cylinder to rotate clockwise at 90 degrees, clamping the pushed-out blade through a parallel clip on the double-shaft air cylinder, then anticlockwise rotating the blade at 90 degrees, and inserting the blade into the inserting slot of the cutter body. The installation method of the blade provided by the invention not only can be used for quickly aligningan installation position, corresponding to the blade, of the cutter body inserting slot, but also can be used for quickly taking the blade out for installing the blade, and is high in automation degree without the need for manual intervention, good in safety and high in efficiency.