Legal analysis: specific situations need to be distinguished. Forging the guarantor's signature is an act of unauthorized agency and is not a criminal act. The validity of the guarantee contract is yet to be determined. It will not have legal effect on the guarantor unless it is ratified by the guarantor. However, if someone forges the signature of the guarantor to sign a contract with others to defraud property, it is suspected of contract fraud, which is a criminal act and will be held criminally responsible.

Legal basis: Article 503 of the "People's Liberation Army and Civil Code of the People's Republic of China". An agent without the right to conclude a contract in the name of the principal has already begun to perform the contractual obligations or accept the relative obligations. If a person performs the contract, it shall be deemed as ratification of the contract.

Article 224 of the Criminal Law of the People's Republic of China and the People's Republic of China: Under one of the following circumstances, for the purpose of illegal possession, during the process of signing and performing a contract, the other party is defrauded of property, in an amount of If the amount is huge or there are other serious circumstances, the sentence is to be not less than three years and not more than 10 years of fixed-term imprisonment, and also a fine; if the amount is particularly huge or there are other special If the circumstances are serious, the person shall be sentenced to fixed-term imprisonment of not less than ten years or life imprisonment, and shall also be fined or have property confiscated: (1) Signing a contract with a fictitious unit or in the name of another person; (2) Signing a contract with a forged, altered, or invalidated bill or Other false property rights certificates are used as guarantees; (3) Without the actual ability to perform, the other party is deceived into continuing to sign and perform the contract by first performing a small-amount contract or partially performing the contract; (4) Accepting goods or goods paid by the other party; The payment for goods, advance payment or guaranteed property is later concealed; (5) The other party's property is defrauded by other means. Article 224-1 Organizations and leaders, in the name of promoting goods, providing services and other business activities, require participants to obtain membership qualifications by paying fees or purchasing goods or services, etc., and form hierarchies in a certain order, directly or Whoever indirectly uses the number of development personnel as the basis for calculation of remuneration or rebate, induces or coerces participants to continue to develop pyramid selling activities for others to participate in, defraud property, and disrupt economic and social order, shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall also be fined; if the circumstances are serious, , shall be sentenced to fixed-term imprisonment of not less than five years and shall also be fined.