The traditional forging technology was studied and improved. The 7.8t propeller-shaft heavy forging was forged through the 4 t electrohydraulic hammer using the reasonable steel ingot and by squaring with 300 mm width flat anvil, stretching, chamfering and rolling processes. Experimental result shows that the defects, such as the shrinkage cavity, porosity, etc., can be clogged by the reasonable forging process. High mechanical properties of the propeller shaft heavy forgings were obtained after quenching and tempering. The characteristics of simple tool, broad universal and large flexible of free forging were fully utilized in this research. The free-forging of long-shaft heavy forging was realized.