Several problems related to the arc behavior of non-copper coated wire in engineering applications are discussed. The results show that the metal droplet transfer form of the non-copper coated wire is the spray transfer under the conditions of high current,strong welding parameters and mixed argon-rich shielded gas,however,when the current is small and the arc voltage is low,the form may be the globular transfer,even short circuiting transfer（when the voltage is very low）. Some substances such as active elements in the non-copper coated wire coating inhibit the adverse effect of CO2 on the arc stability in the arc,which makes the noncopper coated wires have more excellent arc stability than the copper coated wire. The possible adverse effects produced by several key parts in wire feeder and welding gun should not be underestimated. The FFR of the copper coated wires increases by 18.6% and38.8% comparing with that of the non-copper coated wires,but the increase of FFR is not directly proportional to that of copper content in wires.