Abstract: Paragraph 1 of Article 388 of the Civil Code and the Judicial Interpretation of the Guarantee System of the Civil Code provide a clear positive legal basis for atypical guarantees. In this way, China's guarantee legislation has opened a legislative model that adopts both formalism and functionalism. However, the atypical security, which is usually secured by ownership, breaks through the civil law theory of property rights, which is based on the statutory property right, the dichotomy of property and debt, and unified ownership, making it difficult to implant it into the security right system, which brings a certain amount of confusion to judicial practice. Therefore, what needs to be discussed is the possibility of compatibility with the formalism-based security system of atypical guarantees with functionalist characteristics. The combination of formalism and functionalism in the legislative model of guarantee has established a dual pattern of “typical guarantee - atypical guarantee” for the guarantee system. The contractual positioning of atypical guarantees facilitates the application of the principle of autonomy of will and the embedding of the interest balance mechanism, so as to pay attention to the special arrangements of its transactions. At the same time, through the improvement of the screening mechanism of the guarantee function and the subsequent construction of a unified system, that is, the consistency of the establishment, publicity and confrontation, priority and implementation rules of typical guarantee and atypical guarantee, the obstacles of institutional structure and property theory can be overcome, and the juxtaposition and integration of atypical guarantee and typical guarantee in the guarantee system can be realized, so as to provide a theoretical reference for the judicial practice of atypical guarantee and benefit the legal application of atypical guarantee.