Legal analysis: The power of attorney must be signed by both parties. A power of attorney is an expression of the will of both parties. In principle, it requires the signature of the trustee to express recognition of the trust. Once signed, the trust becomes effective. If the parties conclude a contract in the form of a contract, the contract is established when both parties sign or seal it.

Legal basis: Article 490 of the "People's Republic of China and Civil Code" Where the parties conclude a contract in the form of a contract, the contract is established when both parties sign, seal or fingerprint. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established.