The invention discloses a roll shaft spraying mechanism for a prepreg gluing machine. The roll shaft spraying mechanism comprises a first motor and a fixing rack for fixing the first motor. The roll shaft spraying mechanism also comprises a first track group which is slidably connected to the fixing rack. The roll shaft spraying mechanism also comprises a second motor, the power output end of the second motor is connected to a lead screw, and the lead screw is in threaded connection to the fixing rack. By adoption of automatic control, a quite efficient novel roll shaft manufacturing mode is realized, and the roll shaft spraying mechanism is high in rate of finished products and good in effect.