The paper discussed the mechanism of the short circuit transfer process of CO2 gas-arc welding and the cause of the spatter. Several main methods used currently to improve the stability of the short-circuiting transfer arc were described, the advantages and disadvantages of these methods were also analyzed respectively. Chaos control theorem was used to improve the stability, the achievement of which was attained in this field. The development trend of the control methods of improving the stability of short-circuiting transfer arc was indicated.