Abstract: Powder surfacing has been performed by carbon electrode arc constrained by argon in this paper.Its dilution rate is much lower than that of other arc surfacing and its transfer coefficient of alloy elements is high.It is regarded that the lower dilution rate is related to homogeneous distribution of temperature and pressure of the arc and deoxygenization of the arc gas.The depth of melt-pool can be made to be homogeneous by homogeneous distribution of radial temperature and pressure,which leads to the lower dilution rate.The middle temperature has improved deposition efficiency and is benefit for reducing burning of alloys.The deoxygenization of the arc gas and the protection of argon are benefit for reducing burning of alloys so as to increase the transfer efficiency of alloy elements,and increase wettability of the bead layer to workpiece.The synthesis results are that the dilution rate of surfacing of carbon electrode arc constrained by argon is low and the transfer coefficient of alloy elements is high.