Abstract: The authors analyzed some reasons of reducing energy input in welding process by adopting lowenergy-input (LEI) welding, through comparing traditional short-circuit transfer to push-pull short-circuit transfer. By using the self-designed LEI arc welding system and the current wave-form control solution, the authors stated the relation between the short-circuit evening current (I_h) and arc pulse peak-value current (I_ap), and analysed the energy input influenced by energy distributing during short-circuit period and arc period. The paper suggested the method of reducing energy input farther by increasing I_h and decreasing I_ap.