Real estate registration system is a fundamental system in Real Right Law.On the basis of necessity analysis to real estate registration system, this thesis draws an conclusion that registration isn't the declaration of real property rights naturally, but the declaration of real property rights comes to be registration logically.Through revealing the essence of the registration, It concluded that Dingliche Einigung is the constitutive element of establishment of juristic act of real right, and the real estate registration is constitutive element of force of juristic act of real right.And then we analyzed the relationship between Dingliche Einigung and real estate registration.