It is illegal to make a fake contract.

The following circumstances will cause the contract to be invalid when concluding a contract:

1. One party uses fraud or coercion to enter into a sales contract and has harmed national interests;

2. The parties to the buyer and seller contract maliciously colluded to harm the interests of the country, the collective or a third party when concluding the contract;

3. The buyer and seller used legal forms to cover up illegal purposes when concluding the contract, such as Money laundering, etc.;

4. Entering into a sales contract will harm the interests of the public;

5. Violating the mandatory provisions of laws and administrative regulations;

6. Secondly, to establish a sales contract, a necessary condition must be met, that is, both parties must reach an agreement through negotiation. Therefore, a sales contract confirmed by someone else's forged signature is not actually a consensus reached by both parties, so the sales contract has not actually been established.

Legal basis: Article 224 of the Criminal Law of the People's Republic of China

The crime of contract fraud has one of the following circumstances: for the purpose of illegal possession, in In the process of signing or performing a contract, whoever defrauds the other party of property, and the amount is relatively large, shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention, and shall also or solely be fined; if the amount is huge or there are other serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than 10 years. Imprisonment and concurrent fine; if the amount is particularly huge or there are other particularly serious circumstances, the sentence shall be fixed-term imprisonment of not less than ten years or life imprisonment and shall also be fined or confiscation of property:

(1) Using a fictitious unit or impersonating Signing a contract in the name of another person;

(2) Using forged, altered, invalidated bills or other false property rights certificates as security;

(3) Having no actual ability to perform , luring the other party to continue signing and performing the contract by first performing a small-amount contract or partially performing the contract;

(4) Accepting goods, payments, advances or guaranteed property from the other party and then escaping ;

(5) Using other methods to defraud the other party of property.