In recent years, the number of cases of sexual assaults against underage females by family members has risen sharply. The problem of sexually assaulting minors by personnel with special responsibilities has become prominent, and the calls for severe punishment have risen. However, the current provisions of the crime of rape are often powerless for such sexual assault. In response to the public's call, Amendment XI to the Criminal Law added the crime of sexual assault by personnel with care responsibilities, filled the punishment loopholes, and tightened the criminal law network. Persons with special responsibilities such as guardianship, adoption, care, education, medical care, etc., when they have sexual relations with underage females aged 14 to 16, often find that underage females are reluctant despite their superficial consent, which is the reason for the criminalization of this act. There are differences in the degree of violation of will, including partial violation and complete violation of will. The crime of rape is complete violation of will and violates females' absolute sexual autonomy. This crime is partial violation of the will of underage females and violates the relative sexual autonomy of underage females. This crime is not an abstract dangerous crime against sexual autonomy, but a real crime. The legal interest is a pre-legislation concept, which provides the direction and guidance of legislation, while normative purpose is the purpose of legislators to add specific provisions, which is the conclusion after legislation. In order to fully protect the relative sexual autonomy of underage females aged 14 to 16, legislators use legally irrefutable legal presumption in principle. Therefore, the normative purpose of this crime and the protection of legal interests are separated, and the protection scope of normative purposes is greater than the content of protecting legal interests. The reason why there are two diametrically opposite views on the relationship between this crime and the crime of rape is that there are different understandings of whether the violation of will of the victim is the constituent element of this crime. From the perspective of protecting legal interests, this crime and rape are exclusive. However, as far as the normative purpose of this crime is concerned, the violation of will of the victim is not a constituent element of this crime, and there is a competition between this crime and the constituent elements of the crime of rape. The first way to exclude from this crime is to substantively interpret the constituent elements with the protecting legal interests, exclude elements that cannot have a substantial impact on females' sexual autonomy from the constituent elements, and reasonably delineate the scope of application of the constituent elements. The second is to analyze from normative purposes. Judging from the provisions of this crime, in the case of persons with special responsibilities have sexual relations with underage females aged 14 to 16, this crime is an irrefutable legal presumption, but when the victims take the initiative, this crime should be understood as a rebuttable legal presumption. This not only protects the sexual autonomy of underage females aged 14 to 16, but also does not expand the scope of punishment, which is conducive to the dual protection of the legitimate rights and interests of victims and perpetrators.