The Chinese Criminal Procedure Law and related regulations have not clarified the rules on the temporal effect of the application of the law, resulting in difficulties in the transition of criminal procedures from these under the old law to those under the new law. With respect to this issue, the academic circle believes that the principle of applying new procedure law should be applied, but related understandings and definitions are problematic. In terms of normativism, it can be deduced from the principle of immediate application of laws and the principle of non-retroactivity of laws that the law in force at the time when the act is committed should be applied in criminal procedures. For unfinished lawsuits, because the procedures under the new law may not be compatible with the old procedural facts, the application of the law in force at the time when the act is committed will inevitably affect these incompatible old facts, but this is only non-authentic retroactivity, and does not violate the principle of non-retroactivity of laws. However, the non-authentic retroactivity of criminal procedure law may still substantially damage the legal certainty and legitimate expectation, which are exactly the values to be protected by the principle of non-retroactivity of laws. Legislators should follow the thinking path constructed by the theory of legitimate expectation to identify the reliance interests that needs to be paid attention to in advance, and then choose an appropriate legislative plan to incorporate such exceptions into the legal system of criminal procedure. |