Abstract: Thermocouple was adopted to analyze the characteristics of thermal cycle in the heat affected zone welded by laserMAG hybrid welding. The results reveal that the cooling time of the thermal cycle was nearly the same for different positions in the joint. The closer the position was from upper surface and the longer heating procedure was, the longer the residence time upon Ac1 temperature became, and the lower the instantaneous velocity of heating or cooling procedure and the attenuation velocity of the peak temperature were. The gradient and attenuation of peak temperatures at different depths that were a certain distance from the seam center tended to be the same.