Pseudo solder is one kind of familiar solder joint defect, and it is very difficult to be detected in surface mounted technology. Reduce the pseudo solder is viewed as one of effectively way to keep the quality of solder joints. In this manuscript, the quality of component, solder paste printing process, mounting processing, reflowing process, solder material are analyzed to illustrate the cause of pseudo solder in surface mounted technology. Based on the five factors, a pseudo solder model is built for IC component. In the pseudo solder model, its parameters are used corresponding to the cause of pseudo solder, and their values are used to evaluate the degree of satisfaction based on the SMT technological process. Experiments results show that parameters of the pseudo solder model can illustrate the cause of pseudo solder effectively.