The invention discloses a surfacing welding technology for large-area anti-corrosion layers of a tube plate. The technology includes the steps that the tube plate is assembled and positioned, and the portion to-be-welded is cleared; welding equipment is installed and debugged, and welding technological parameters are input; straight welding pass surfacing welding is carried out at the primary side of the tube plate, after one layer is formed through surfacing welding, the tube plate is turned over by 180 degrees, and straight welding pass surfacing welding is carried out at the secondary side of the tube plate; welding operation is repeated until the anti-corrosion layers of the specific thickness are formed at the two sides of the tube plate. According to the welding technology, the deformation of the tube plate can be as low as 1 mm or below after the welding technology is completed, the welding process is stable, weld joints are formed uniformly, fusion between layer passes is good, and the requirement for welding quality of nuclear island main equipment can be met.