The success of the principle of legality relies on its realization in judicial practice. Existing researches focused on institutional improvements at the macro level and legal interpretation at the micro level, but both approaches are centered on power and lack of practicability. A necessary adjustment is to rely on procedural mechanisms, including multi-layer review, group decision-making, adversarial and open trial, disclosure of court opinions and guidance by precedents, to enhance the precision of legal findings and its compatibility with the facts. Such a procedural approach, in addition to constitutional, legislative and judicial improvements, may eventually realize the principle of legality in practice.