Abstract: The influences of welding parameter during laser- MIG hybrid welding of 5A06 aluminum alloy on weld penetration were investigated.And weld penetrations of welding techniques as laser-MIG hybrid welding, MIG welding and laserwelding were compared and analyzed.The results show that if MIG arc power being equivalent to 2000W laser power penetration was taken as a dividing line, the MIG arc power can be divided into two parts.One is higher power MIG arc zone, the other is lower power MIG arc zone. Combining 2000 W laser power with lower power MIG arc, it is found that laser power determines hybrid weld penetration.The weld penetration of hybrid welding was deeper than that of MIG welding. However, the 2000 W laser power was combined with higher power MIG arc, the hybrid weld penetration was maialy determined by MIG arc power.The hybrid welds showed key characters of MIG weld. The advantages of integrating laser power into MIG welding represent primarily increasing welding speed of hybrid welding.