The invention relates to a welding fixture. The welding fixture comprises a workbench base, double-side welding combined clamping plates and sliding rails which are connected to the workbench base, a welding operating table used for placement of a weldment, brackets connected to the workbench base, a front fixture rotating plate and a rear fixture rotating plate which are connected via a rotating shaft and can rotate around the rotating shaft clockwise or anticlockwise, and slideable fixtures, sliding grooves and liftable supporting rods which are positioned on two sides of the front fixture rotating plate. According to the invention, the automaton of welding turnover is realized through rotation of the double-side welding combined clamping plates, the influence on the welding quality due to turnover originally is reduced, the operation of workers is simplified, only few manual operation is needed, requirements for the degree of proficiency and operating techniques are lower, the quality of welding products is guaranteed, and the welding efficiency and automation degree of double-side welding are improved.