The invention discloses a paper feeding device of a carton printing machine. The paper feeding device comprises a bracket (1) with an opening, wherein a top roller (2) and a bottom roller (3) are arranged at the opening; a paper feeding port (4) is formed between the top roller (2) and bottom roller (3), and is over against a paper feeding workbench (5); the paper feeding workbench (5) consists of two rotation rollers (6) and a belt (7) arranged on the two rotation rollers (6); raised strips (71) are arranged on the outer surface of the belt (7) along the directions of shafts of the rotation rollers (6); a drying plate (9) with infrared lamp tubes (91) is arranged at the upper part of the paper feeding workbench (5); baffle plates (8) arranged at the two sides of the belt (7) are formed downwards at the left side and the right side of the drying plate (9); and a gap is formed between each baffle plate (8) and the belt (7). With the adoption of the paper feeding device of the carton printing machine, paper feeding can be exact, and the printing effect is good.