The invention discloses a full-automatic carton packing machine with an improved structure. A cuboid type case is arranged below the carton packing machine, two steel planks for placement of a cartonfor packing are arranged on the case, and each steel plank is supported by two stand columns; two guide tracks are arranged beside the left steel plank, and an adhesive tape device pneumatically slides on the guide tracks; a sucker device and three cylinder devices are arranged in the case, and the front ends of piston rods of the three cylinder devices are warped steel plates for forming of cartons; and an inverted-'L'-shaped stand column is arranged on the left of each of the two guide tracks, a cylinder device is arranged at the upper end of each stand column, the bottom of each stand column is connected with a '['-shaped device through three piston rods of a cylinder, two cylinder devices are separately arranged at two front ends of each stand column, and the structures of the cylinderdevices are similar to the structures of the cylinder devices in the case. Motion of all the cylinder devices and motion of a carton sucker can be implemented through a master controller and a touchdisplay screen. By the full-automatic carton packing machine, full-automatic packing is realized through the various devices on the basis of the original carton packing machine. The full-automatic carton packing machine with the improved structure is simple in structure and simple and convenient to operate, and the packing efficiency can be improved.