Legal analysis: China's contract law does not stipulate that a contract is only useful if its handprint or seal is red. As long as it is signed by both parties voluntarily and its contents conform to the law, it is legally effective.
legal basis: article 49 of the civil code of the people's Republic of China
if the parties conclude a contract in the form of a contract, the contract shall be formed when all 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 writing as stipulated by laws and administrative regulations or agreed by the parties. If the parties fail to do so in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.
article 493 where a contract is concluded by the parties in the form of a contract, the place where the contract is formed shall be the place where the parties finally sign, seal or fingerprint it, unless otherwise agreed by the parties.