Abstract: A typical plastic ball grid array (PBGA)component was selected and the plastic ball grid array packaging was modeled as a tri-layer structure composed of encapsulation, die and substrate.Visco-plastic model was used to describe the behavior of SnPb solder.ANSYS finite element analysis tool was used to implement the simulation.In the end, the stress and strain distribution were obtained.The strain range was achieved from the hysteresis loop. The fatigue life of PBGA was predicted using Engelmaier model.The simulation result of the model shows that the position of the critical soldered position of a plastic ball grid array component is right below the edge of its die, but not the outboard solders.This result is helpful to improve the thermal fatigue reliability of plastic ball grid array components.