The invention discloses a special opening agent for polyethylene film, and belongs to the technical field of high polymer materials. The special opening agent is prepared by adopting the steps that (N-amidino)dodecyl acrylamide and a polyethylene glycol derivative are mixed according to the mass ratio being (1:1)-(2:1), paradichlorobenzene with the mass being 0.1-0.2 time of the polyethylene glycol derivative and ferrocene with the mass being 0.07-0.10 time of the polyethylene glycol derivative are added, and then stirring is conducted, and a modified additive is obtained; and a filling material, sodium benzoate, the modified additive, calcium bicarbonate, an antioxidant, carbomer, alkaloid, phospholipid, modified diatomite and water are placed in a beaker, and then the beaker is placed ina ultrasonic dispersion device to be subjected to ultrasonic dispersion for 30-50 minutes under the condition that the ultrasonic frequency is 55-65kHz, and the special opening agent for the polyethylene film is obtained. The special opening agent for the polyethylene film provided by the invention has an excellent opening property.