The drafting of Article 6 of the European Convention for the Protection of Human Rights and Fundamental Freedoms indicates the adversarial core of this Article.The history of the judicial precedents of European Court of Human Rights on confrontation right is the history of the slow development of its adversarial core.In dealing with problems of confrontation right, the European Court of Human Rights established a two-tiered analytical approach.Via this approach, the safeguard of confrontation right is taken back into the vision of fair trial for consideration.In order to implement the two-tiered analytical approach, the European Court of Human Rights created a three-steps test, that is, to examine step by step the reasonable basis for the witness not appearing in court, whether the written testimony is the only or conclusive evidence against the defendant, and whether there are other balance factors to offset the adverse effects caused by written testimony to the defendant.Learning from the European Court of Human Rights, China should make clear the substantive requirements and the procedural requirements for the attendance of key witnesses, the conditions of non-attendance of key witnesses and the criterion to distinguish them.