The invention relates to a filter layer expanding and loosening manipulator in an automatic filter element assembly line. Four expanding and loosening devices are fixedly mounted below four feed pipes, two oscillating cylinders are hinged to a lifting plate in reverse symmetry, and piston rods of the two oscillating cylinders are connected with cranks on the four expanding and loosening devices through transition connecting rods pairwise. Every expanding and loosening device comprises an oscillating sleeve, four connecting rods, four oscillating rods, four expanding and loosening rods and the like, the connecting rods and the oscillating rods are mounted below the feed pipes and the lifting plate through second pin screws and third pin screws respectively, every oscillating sleeve is mounted outside the corresponding feed pipe through a bearing, and every crank is mounted on the corresponding oscillating sleeve. A first pin screw penetrates through the middle of every oscillating rod and is tightened on the connecting rod corresponding in position, and one expanding and loosening rod is fixedly mounted at the front end of every oscillating rod vertically. Along with that the oscillating cylinders extend out, the oscillating sleeve of every expanding and loosening device is pushed to rotate clockwise to drive the outer ends of the connecting rods to push the oscillating rods away from the direction of the second pin screws through the first pin screws so as to enable the four expanding and loosening rods to expand outwards synchronously, and filter layers are stretched radially to be expanded and loosened accordingly.