In order to increase the hole filling of large-area copper overlaid in multilayer PCB in model products， in this study， a three-dimensional model of four-layer large-area copper-clad through-hole soldering was established. By studying the temperature field distribution during the through-hole soldering process of a four-layer copper-clad printed board after added temperature compensation， the influence of soldering temperature on the solder penetration was concluded. It was found that the through-hole solder penetration reached 100% at the soldering temperature of 350 ℃， which is consistent with the actual soldering result that all solder joints reached 100% solder penetration. The finite element temperature simulation results are in good agreement with the thermocouple temperature measurement results， indicating that the model can accurately simulate the temperature evolution during the soldering process， and provides theoretical guidance for the manual soldering process and soldering parameter optimization of large-area copper-clad through-hole solder joints. It has very important research significance for ensuring the solder penetration rate of the through-hole solder joints， and then ensuring the production quality of the products.