Packing type plunger net screen changer includes cylinder block and plunger rod, plunger rod is connected with linear power mechanism, plunger rod is placed in cylinder block, plunger rod can slide relatively between plunger rod and cylinder block, plunger rod can extend along one end of cylinder block, filler is arranged at the other end of cylinder block, conical surface and cylinder block are arranged at the root of the extended end of plunger rod. There is a closed line contact between them.