Abstract: Natural protected areas achieve biological carbon sequestration in the form of carbon preservation. The carbon pool in natural protected areas plays the role of a carbon sink rather than a carbon source, and the carbon sink has stability and durability. Thus, the carbon sink function of natural protected areas can contribute to the realization of the “carbon emission and carbon neutrality goal” in China. In the national land space, natural protected areas are included in the ecological protection red line, a special plan is formulated for them, and the use of natural ecological space of natural protected areas is regulated. Therefore, the carbon sink function of natural protected areas shows an institutional advantages in LULUCF. However, the ownership of natural resources in natural protected areas is diverse and the stability of the carbon sink function in natural protected areas will inevitably be affected. At the same time, carbon sinks, as non-traditional property interests, have not been clearly defined as property rights in private law. The lack of carbon sink ownership rules in private law has become an institutional obstacle to the realization of carbon sink function in natural protected areas. To this end, laws, including the Civil Code, should be amended, take the biological carbon sink as an independent property interest, and clarify the attribution rules for the biological carbon sink interest. Carbon sink projects in natural protected areas should be specified as nationally certified voluntary emission reduction projects in carbon emission trading that can be used for offset first.