The utility model discloses an automatic screen printing machine which comprises a rack, a workbench and a screen printing mechanism, and is characterized in that a damping sliding rail and a punchingmechanism are further arranged on the left side of the workbench; the punching mechanism comprises a sliding block, a supporting block, an L-shaped plate, an air cylinder and a punching needle. The sliding block is arranged on the damping sliding rail in a sliding mode. The supporting block is installed on the sliding block. A notch is formed in the front side of the bottom of the supporting block; the air cylinder is installed over the supporting block through the L-shaped plate. An output shaft of the air cylinder penetrates through the L-shaped plate and is arranged above the supporting block; an upper through hole is formed in the supporting block, a lower through hole is formed in the sliding block, the upper through hole is communicated with the lower through hole, the top of the punching needle is connected with an output shaft of the air cylinder, and the bottom of the punching needle penetrates through the upper through hole to be inserted into the lower through hole. According to the utility model, the punching efficiency is improved, the cost is reduced, and the silk-screen printing efficiency and quality are ensured.