Hello, does the contract become valid as long as it is signed? The contract does not necessarily become valid after being signed. If there are some circumstances, the contract will be invalid or partially invalid. Circumstances in which a contract is invalid: 1. One party concludes the contract by means of fraud or coercion, thereby harming national interests. 2. A contract that maliciously colludes and harms the interests of the country, the collective or a third party. 3. Concluding a contract in a legal form to cover up illegal purposes. 4. A contract that harms the interests of the public. 5. Violates the law. Contracts subject to mandatory provisions of administrative regulations.