As the core content of the abstract principle of due process, it consists of the neutral standard, participation standard and timing standard. However, it still has the certainty and uncertainty. This article finds that the existence of the principle of due process present diversity in the continental legal family, and the application of the principle of due process in the administrative litigation encounters a lot of confusion due to the absence of legislation by anglicizing empirically the authoritative cases. The vitality of the principle of due process present the concrete of legislation or Justice. In view of the fact that it is difficult to satisfy the society with the concrete of legislation, and the lag of legislation is inevitable, how to concrete justice is the key point and difficulty which the principle encounters in judicial practice. The highest judicial organ should introduce "due process" principle to be used as the standard of judicial review in judicial interpretation of the new "administrative procedural law" to prevent the judicial arbitrary and eliminate the pressure from the application of the "administrative procedural law" in the future, and at the same time clear the following the train of thought how to apply the principle of due process : prior to due process , the court applies the normal legal procedure, only when facing hard cases on procedure can the court applies the principle of due process. The above hard cases are consist of five types namely: fuzzy rulesRthe concurrence of rules, the review on the administrative discretion ,the gap-filling of law ,principle paradox. The court chooses a suitable way of judgment and reasons accurately and properly it according to different hard cases on procedure ,which is the key of the concrete of the principle of due process.