According to Article 5 of Interpretation of Contract Law (II), both parties shall sign or seal it in writing. However, if the parties are unable to sign a contract due to special circumstances, the people's court shall determine that it has the same legal effect as signing or sealing. That is to say, any kind of written contract can only achieve the function of written form in law after it is stipulated in some way, and it is legally binding on the parties. The signature, seal and handprint of the parties are all legally recognized ways. Therefore, the act of fingerprinting has the same legal effect as the signature, and it is a true expression of meaning. Signature and thumbprint have the same legal effect, but in practice, the most prudent choice is to use both signature and thumbprint.