In 1997, Taiwan district abolished the prosecutor's decision-making power of pretrial custody, and adopted a number of reform measures of custody system, such as establishing the principle of pre-arrest and the principle of custody claim, refining the applicable elements of custody, establishing the custody hearing system, and so on. The implementation effect of the pretrial custody rate has been greatly reduced. The change of pretrial custody decision-making power in Taiwan directly reflects the evolution of the attitude of all sectors of society towards the essence of judicial power and the concept of criminal justice. It is based on the gradual promotion of several measures such as the division of trial and prosecution, the improvement of the status of judges and so on. It is also driven by the hot cases that have aroused widespread public attention and legal debates. This paper summarizes the reference significance of the change of pretrial custody decision-making power in Taiwan district, which not only reflects the development requirements of modern criminal law that the power allocation of pretrial custody should follow the principle of separation of powers and the custody review procedure should adopt the litigation structure, but also reveals the fact that the smooth progress of the change of custody decisionmaking power depends on the achievement of various conditions.