Laser soldering was used to correct joint problems in the lateral electrodes of piezoelectric ceramic transformer (PECT). Wire-mesh and soldering paste were used to weld te lateral electrode of a PECT. The joint problem in multilayer heterogeneous lamination was corrected with this process so that the PECT were connected very well and were not affected much by heat. A three-dimensional model was developed for the laser soldering temperature field in multilayer materials. A simplified model was used for efficient finite element analysis to investigate the temperature distribution characteristics in laser soldiering. The results were verified experimentally. The analysis of the temperature field distribution during laser soldering will accelerate the application of PECT and will be a reference for similar problems.