The utility model discloses an automobile air conditioner with a novel air door movement mechanism. the mode sliding disc is provided with a positioning shaft hole; the mode sliding disc is limited onthe automobile air conditioner shell through a rotating shaft arranged on the positioning shaft hole; a driving boss is arranged on the mode sliding disc; the surface blowing air door and the defrosting air door are connected with the surface blowing air door rotating shaft through keys and are coaxially arranged; a first guide rail groove and a second guide rail groove are formed around the modesliding disc; a second moving column is arranged at one end of the foot blowing deflector rod; the second moving column slides in the second guide rail groove; the other end of the foot blowing deflector rod is buckled on a foot blowing air door rotating shaft arranged on the foot blowing air door; one end of the transition connecting rod is provided with a first moving column, the first moving column slides in the first guide rail groove, the other end of the transition connecting rod is hinged to the face blowing defrosting deflector rod, the other end of the face blowing defrosting deflector rod is buckled to the face blowing air door rotating shaft, and then the three air doors are synchronously driven by the one-mode sliding disc to move synchronously, so that all the air doors are matched.