The purpose of this paper is to study the ability of solder joints to resist thermal fatigue. 2D simplified models of Plastic Ball Grid Array package (PBGA) structures with ten different solder joints obtained from surface mount experiment are established by finite element software, then stress-strain response of solder joints subjected to the thermal cycle load are calculated. And the effects of shape parameters of solder joints on the ability to resist thermal fatigue are discussed. Results indicate that for the same material and volume solders, the solder joints which have higher height, smaller diameter and contact angle have a stronger ability against thermal fatigue, and that the thermal fatigue characteristics are also greatly influenced by the solder outlines. Comparing with SP solder joints, LF solder joints have stronger ability against thermal fatigue.