Microstructure and segregation behavior during solidification in GTAW deposited metal of new type nickel alloy welding wire are investigated by OM,SEM and EDS. The results show that both metallographic structure of deposited metal of welding wire 1# and 2# is similar columnar crystal with interdendritic segregation zone, but no Laves+γ eutectic structure exists in 2# deposited metal.The partition coefficients of Nb,Ta,Mo at the beginning of solidification are less than 1,which incline to distribute in residual liquid phase during crystallizing. The partition coefficients of Fe at the beginning of solidification is over 1,which inclines to distribute in solid phase. Ni and Cr tend to evenly distribute between liquid and solid phase. Adding Ta in welding wire 2# has no obvious influence on partition coefficients of other elements,while has significant effect on microstructure,which avoids the formation of low melting point Laves+γ eutectic structure and then shortens the crystallizing temperature interval.