3-D finite element models of SOP（ Small Outline Package） were constructed,in which Anand visco-plasticity constitutive equation was used to describe the mechanic behavior of solder joint. The solder joint deformation and stress distribution with five kinds of lead shapes were researched. The experimental program for the identification of numerical simulation was performed with three kinds of lead shapes. Both experimental and simulation results showed that the solder joint life is closely related with lead shape. The lead shape with low stiffness can decrease the stress apparently. With decreasing the bending radius or increasing the standoff height,the component reliability will be enhanced. The numerical simulation result was congruous with experimental testing data,can able to reflect the factual behavior of SOP accurately.