If buying and selling a house is the behavior of both husband and wife, it needs to be signed by both parties. However, if one spouse entrusts the other spouse to sign, only one spouse will sign. Article 161 of the Civil Code of People's Republic of China (PRC) * * * A civil subject may carry out civil juristic acts through an agent. Article 165 If the power of attorney is in written form, it shall specify the name of the agent, the matters to be represented, the authority and the time limit, and shall be signed or sealed by the principal. Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. 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.