The invention discloses an automatic film pasting machine for mobile phone. The automatic film pasting machine comprises a manipulator, a material box, a sucker, a mobile phone positioning device, a mobile phone protection piece positioning device, a mobile phone cleaning device and a film tearing device; the mobile phone cleaning device comprises a lifting motor, a plasma cleaning spray head anda secondary cleaning rubber roller, wherein the lifting motor drives the plasma cleaning spray head and the secondary cleaning rubber roller to perform lifting motion, the film tearing device comprises a tearing mechanism and a film clamping mechanism, the film clamping mechanism comprises a clamping plate motor, a lifting base and a film piece clamping portion mounted on the lifting base, and theclamping plate motor drives the lifting base to drive the film piece clamping portion to move up and down; and the tearing mechanism comprises a sliding plate support and a driving unit used for driving the sliding plate support to move. The automatic film pasting machine has the advantages that the film pasting efficiency is not improved, and the cleaning effect is more thorough, the positioningof the mobile phone protective film is more accurate, adhesive tape is not needed during film tearing, the adhesive tape cost is saved, meanwhile, and the film tearing success rate is high.