This article aims to analyse the statutes and cases as to sexual morality offences which involve sexual ethics in society and make a proposal of idealistic sexual criminal law.Out current criminal law deals with sexual crimes in the way that divides sexual violent crimes with sexual morality crimes: the former violates the private right of sexual self-determination, and the latter decays the public decency. Of them the sexual morality crimes involve social environment and ethics. Especially the statues and cases of sexual morality crimes reflect social ever-changing ethics after 1990s and the perspectives of the scholars and specialists. And a various of NGO as well as interest groups have deeply involved with the legislation of kinds of sexual criminal laws just like Prostitution Act, Protection of Juvenile sex Act, Sexual Violence Act etc. To regulate sexual morality crimes reasonably, I suggest, needs the following alternative: to extract ethical element from the criminal law, respect the private right of sexual self-determination, keep alert about penal populism, and in the end, it is required that sexual moral crimes must be decriminalized and sex crimes are integrated in terms of the right of sexual self-determination.