Abstract: A novel AC shortcircuit tansfer was presented.According to the welding heat input control based on the EN and EP transition, the arc instability and exclusion have been improved.In order to make the energy control continuous, double transition was implemented in each cycle.This method can control the energy during welding process with the heat distribution control of the base metal and wire.The welding machine designed for this method can meet the technical requirements and realize service reliability and precise output.The experimental results indicate the AC shortcircuit tansfer technique has stable welding with the less spatter and the good weld bead.