Abstract: A ring-shaped pattern macro-structure in Φ300 mm forged bar of S53 steel melting by a 6 t vacuum consumable enectrode furnace is found,analysis by structure and SEM shows that segregation of Cr,Mo and other elements is the cause of ring pattern formation. By vacuum consumable smelting parameters adjusted ， the droplet short circuit time reducing from 0. 8 s to 0. 3 s on average,the voltage value decreasing from an average of 26 V to 25 V, the melting rate decreasing from an average of 6 kg/min to 4. 8 kg/min,the current value decreasing from an average of 11 500 A to 7 500 A, helium pressure reducing from an average of 600 Pa to 300 Pa,the ring pattern structure of S53 steel is eliminated.