The invention discloses an automatic film connecting mechanism of a thermal shrinkage film packaging machine. The automatic film connecting mechanism comprises a film connecting rack, a roller, film pressing air cylinders, film fixing air cylinders, film fixing bases, film connecting air cylinders, a film connecting device, film breaking air cylinders, a film breaking device and air bulking shafts; the air bulking shafts, the film breaking air cylinders, the film connecting air cylinders, the film fixing air cylinders and the roller are sequentially arranged in the conveying direction of film. By means of the automatic film connecting mechanism, in the continuous high-speed film packaging production process, the roll of film can be automatically connected with another roll of film in a butt-joint mode after being used up, the production continuity is guaranteed, and real full-automatic production is achieved. The automatic film connecting mechanism can achieve automatic high-speed film cutting and connecting on the condition that the equipment does not stop or slow down and conducts normal high-speed film feeding, and a large amount of waiting time and preparing time are saved.