The preventive measures regarding security provided in current laws could be divided into two categories: One is that the subject has committed an offence or a criminal illegal act, and such a measure is used to prevent him from committing offences or criminal illegal acts again. The other is that the subject has committed an act against administrative law which does not violate criminal law, and such a measure is used to prevent him from committing an offence in future. The measures in the first category should be regulated in a specific chapter of penal code. Its significances are as follow: to implement the principles and spirit of constitutional law; to resolve the chaos among criminal laws and administrative laws; to keep the equal application of different measures which having same functions. Stipulating such measures in a specific chapter of penal codes could clarify the legal position and nature of them in order to prevent abuse of them.