It depends: first, if the actor has no power of attorney, exceeds the power of attorney, or the contract signed in the name of the principal after the power of attorney is terminated, it will not be effective for the principal without ratification by the principal, and the act of signing someone else's name with his own handprint will be invalid.

Second, if it does not meet the above conditions, it is effective to sign other people's names according to your own fingerprints. According to Article 490 of the General Principles of the Civil Law, if the parties conclude a contract in the form of a contract, the contract is established when the parties sign, seal or press their fingerprints. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it. A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.

legal ground

Article 490 of the Civil Code of People's Republic of China (PRC), when concluding a contract, if the parties conclude the contract in the form of a contract, the contract shall be established when the parties sign, seal or press their fingerprints. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it. A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.