Article 192 of the Civil Code is the general rule the effect of expiration of extinctive prescription，and article 193 is the prohibition rules of authority. The occasion，subject，form and effect of invoking the right to defense of extinctive prescription should be determined under the framework of“doctrine of right of defense”，the invoking behavior is also restricted by the principle of good faith. If the obligor agrees to perform after the expiration of the limitation period，it constitutes an act of waiving the right to defense of extinctive prescription in an express form，the form and effect of the waiver should be determined on this premise. If the obligor has performed the obligations voluntarily after the expiration of the limitation period，it belongs to the performance with legal reasons and does not constitute unjust enrichment，the form and effect of voluntary performance should be determined on this premise.