Legal analysis: Blue signature pens have legal effect, but Chinese law does not have mandatory regulations on which color pen should be used to sign a contract.

Legal basis: "People's Republic of China and Civil Code"

Article 490: Where the parties conclude a contract in the form of a contract, both parties shall sign, seal or The contract is formed when the fingerprint is pressed. 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.

Article 491: If the parties conclude a contract in the form of letters, data messages, etc. and require the signing of a confirmation letter, the contract shall be established when the confirmation letter is signed.

If the goods or service information released by one party through the Internet or other information networks meets the conditions of the offer, the contract will be established when the other party selects the goods or services and successfully submits the order, unless otherwise agreed by the parties.