The welding method and technology of the water heater tank in the solar water heater industry are introduced. And the argon tungsten arc welding and electric resistance seam welding commonly used for the atmospheric pressure solar vacuum heat pipe water heater tank,and their welding technologies and technical points are mainly expound. Finally,the CO2 gas shielded arc welding and its welding technology for the pressure type solar water heater tank are briefly introduced. It is hoped to provide some reference for the relevant personnel engaged in the manufacturing of solar water heater tank.