Abstract: The three point bending stress and strain finite element analysis model of embedded substrate micro scale grid electrode array welding spot is established. The influence of solder joint material, spot distance, PCB support span and solder joint array on the bending stress and strain of solder joints is analyzed. The results show that the maximum BGA solder joint of embedded substrate is maximum under the condition of three point bending loading. Bending stress and strain all appear on the solder joints at the most peripheral corner. When the three point bending load is loaded to the same displacement load:the bending stress of the solder joint of the SAC387 material is the largest, the bending stress of the solder joint of the 62Sn36Pb2Ag material is the smallest, and the maximum bending stress and strain in the solder joints decrease with the increase of the span of the support, and the maximum bending stress and strain inside the solder joints increase with the increase of the distance between the BGA solder joints. With the increase of the number of BGA solder joints, the maximum stress and strain values of solder joints increase.