The invention discloses a method for quickly disassembling and assembling screws of a double-screw extruder. The method is easy to implement and short in disassembling and assembling time. The method is realized mainly through the following steps that step 1, before the screws are disassembled, the temperature of a cylinder is raised to approximate 300 DEG C; step 2, the screws are rotated, nylon materials left on the cylinder and carried in PE last time are cleaned clearly by PE materials, and then lubricating agent ethylene bias stearamide and linear low-intensity polyethylene are mixed to clean the screws again; step 3, screw rotation is stopped, an extruder die head is opened, and the screws and set screws of sleeves are unscrewed; step 4, after the double-screws are pulled out, the double-screws are cleaned through copper brushes; step 5, the cylinder is blown clearly through an air gun, and newly-assembled screws are installed. The method is easy to implement, short in screw disassembling and assembling time, high in efficiency and low in equipment cost.