The Civil Code provides guarantees for debt can be mainly divided into two categories: “guaranty” and “mortgage”. The former is based on the guarantor’s capital or credit as a guarantee for debt performance; the latter is mainly based on the way that guarantor directly provides the mortgage for the property. Some scholars believe that mortgage and civil guarantor are different in nature. Owing to this, the legal principles and provisions applicable to civil guarantor, in principle, do not automatically apply to mortgage. In spite of this, if viewed from their respective purpose, these two types of guarantors both offer their properties as security for the principal debtor and are obliged to satisfy the debt payment with their properties when the principal debtor fails to perform the debt obligation owed to the creditor. It is difficult to distinguish the differences and similarities between these two types of guaranty systems. Although the Civil Judgment Appeal-892 by Taiwan High Court in 2017 appeared to be representative of legal opinions on Civil Code Article 742 (1) could be applied by analogy to Mortgage, it is still necessary to further clarify and discuss Civil Code Guaranty Article may be applied by analogy to Mortgage. As a result, this article is intended to discuss whether there are common legal applications to these two apparently different but highly correlated guaranty systems and clearly identify their differences and similarities.