Abstract: With the modern social security system being established, the civil liability law has been questioned for its necessity of existence, and thereby suffered from an unparalleled "survival crisis" seemingly. However, the modern social security system cannot resolve the problem of people's mental interests protecting. Mental interests protecting makes the civil liability law irreplaceable. The civil liability law lies in its morality nature; any theory could not justify itself when it interprets civil liability law against morality principle; both the modern social remedy theory and its practice are not able to deny civil liability law's repaying mechanism and its inherent function.