The aim of the testimony system is to discover the fact that happened previous And the realization of the aim can also make clear who tell the truth between the litigants, and this can also help the judge make a correct judgment But what we concern in legislation and judicatory practice are the substance of the testimony The form of the testimony is ignored This is very pity In this article, the author want to set forth the importance of the testimony form, using the theory of epistemology and psychology, and give some advices on how to design the relative systems