The comprehensive utilization of rainwater resources is of great significance to alleviate the urban waterlogging and the contradiction between the supply and demand of water resources. However, the domestic research on rainwater resources utilization and management authority mainly centers on the field of engineering technology. There are few studies dealing with laws, regulations and policies, which can not meet the needs of rainwater resources development and utilization. In the context of China’s Civil Code, the paper focuses on the perfection of the system of the ownership of rainwater resources and makes legislative investigation and theoretical analysis of the ownership and utilization of rainwater resources both at home and abroad from the perspective of comparative law. The results show that water resource is a kind of commodity collected by labors, which is unique and different from the traditional surface water and groundwater. The ownership of rainwater resources is enjoyed by civil subjects such as natural persons, legal persons and unincorporated organizations by means of accession, but the construction of rainwater collection facilities should be incorporated into the administrative examination and approval procedure. In this way, the legal system of rainwater resources utilization is gradually improved by clarifying the ownership of rainwater resources to solve the difficult problem of longterm sustainable use of rainwater resources.