Abstract: The condition adaptability of 2A14 and 5A06 aluminum alloys to variabe polarity plasma arc welding（ VPPAW） was studied. The results showed that,compared with 5A06 aluminum alloy,2A14 aluminum alloy has better condition adaptability to VPPAW,and has a wide range of adaptability to parameters such as gap and pair height difference. The difference of solid and liquid temperature,thermal conductivity,specific heat capacity and other thermal properties of the two materials is an important reason for the difference in condition adaptability.