Abstract: The infrared thermal imaging system was used as a sensor to measure the temperature field of wrought magnesium alloy AZ31B during the laser-TIG hybrid welding process.And a method for calibrating the welding temperature field was proposed, that was based on the infrared temperature measurement theory and was directed toward the infrared thermal imaging system.Thermocouple was applied to verify the accuracy of the calibrated method. And numerical simulation method was used to simulate the whole welding temperature field. The experiment results showed that real temperature calibrated method was able to calibrate the temperature field accurately when the plate surface condition was uniform, and surface calibrated method was able to keep the influence caused by the plate surface condition alternation from the temperature field distribution. With the combination of real temperature calibrated method and surface calibrated method, exact temperature field of magnesium alloy outside the arc covering area during laser-TIG hybrid welding process was obtained. Welding temperature field numerical simulation method was able to forecast and reflect the real distribution of whole welding temperature field accurately.